Repository: helix Updated Branches: refs/heads/master e0148917d -> 39e0d3fb0
http://git-wip-us.apache.org/repos/asf/helix/blob/39e0d3fb/website/src/site/markdown/Architecture.md ---------------------------------------------------------------------- diff --git a/website/src/site/markdown/Architecture.md b/website/src/site/markdown/Architecture.md new file mode 100644 index 0000000..1d724ad --- /dev/null +++ b/website/src/site/markdown/Architecture.md @@ -0,0 +1,249 @@ +<!--- +Licensed to the Apache Software Foundation (ASF) under one +or more contributor license agreements. See the NOTICE file +distributed with this work for additional information +regarding copyright ownership. The ASF licenses this file +to you under the Apache License, Version 2.0 (the +"License"); you may not use this file except in compliance +with the License. You may obtain a copy of the License at + + http://www.apache.org/licenses/LICENSE-2.0 + +Unless required by applicable law or agreed to in writing, +software distributed under the License is distributed on an +"AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY +KIND, either express or implied. See the License for the +specific language governing permissions and limitations +under the License. +--> + +<head> + <title>Architecture</title> +</head> + +## Architecture + +Helix aims to provide the following abilities to a distributed system: + +* Automatic management of a cluster hosting partitioned, replicated resources +* Soft and hard failure detection and handling +* Automatic load balancing via smart placement of resources on servers (nodes) based on server capacity and resource profile (size of partitions, access patterns, etc) +* Centralized config management and self discovery, eliminating the need to modify config on each node +* Fault tolerance and optimized rebalancing during cluster expansion +* Management of the entire operational lifecycle of a node. Add, start, stop, enable, and disable without downtime +* Monitoring of cluster health and alerting on SLA violations +* A service discovery mechanism to route requests + +To build such a system, we need a mechanism to coordinate between different nodes and other components in the system. This mechanism can be achieved with software that reacts to any change in the cluster and comes up with a set of tasks needed to bring the cluster to a stable state. The set of tasks will be assigned to one or more nodes in the cluster. Helix serves this purpose of managing the various components in the cluster. + + + +## Distributed System Components + +In general any distributed system cluster will have the following components and properties: + +* A set of nodes also referred to as __instances__ +* A set of __resources__ which can be databases, lucene indexes or tasks +* Subdivisions of each resource into one or more __partitions__ +* Copies of each resource called __replicas__ +* The __state__ of each replica, e.g. Master, Slave, Leader, Standby, Online, Offline, etc. + +## Roles + + + +Not all nodes in a distributed system will perform similar functionalities. For example, a few nodes might be serving requests and a few nodes might be sending requests, and some other nodes might be controlling the nodes in the cluster. Thus, Helix categorizes nodes by their specific roles in the system. + +Helix divides nodes into 3 logical components based on their responsibilities: + +1. __Participant__: The nodes that actually host the distributed resources +2. __Spectator__: The nodes that simply observe the current state of each Participant and routes requests accordingly. Routers, for example, need to know the instance on which a partition is hosted and its state in order to route the request to the appropriate endpoint +3. __Controller__: The node that observes and controls the Participant nodes. It is responsible for coordinating all transitions in the cluster and ensuring that state constraints are satisfied while maintaining cluster stability + +These are simply logical components and can be deployed according to system requirements. For example, the Controller: + +1. can be deployed as a separate service +2. can be deployed along with a Participant but only one Controller will be active at any given time. + +Both have pros and cons, which will be discussed later and one can chose the mode of deployment as per system needs. + +## Cluster State Metadata Store + +We need a distributed store to maintain the state of the cluster and a notification system to notify if there is any change in the cluster state. Helix uses [Apache ZooKeeper](http://zookeeper.apache.org) to achieve this functionality. + +Zookeeper provides: + +* A way to represent PERSISTENT state which remains until its deleted +* A way to represent TRANSIENT/EPHEMERAL state which vanishes when the process that created the state dies +* A notification mechanism when there is a change in PERSISTENT and EPHEMERAL state + +The namespace provided by ZooKeeper is much like that of a standard file system. A name is a sequence of path elements separated by a slash (/). Every node (ZNode) in ZooKeeper\'s namespace is identified by a path. + +More info on Zookeeper can be found at [http://zookeeper.apache.org](http://zookeeper.apache.org) + +## State Machine and Constraints + +Even though the concepts of Resources, Partitions, and Replicas are common to most distributed systems, one thing that differentiates one distributed system from another is the way each partition is assigned a state and the constraints on each state. + +For example: + +1. If a system is serving read-only data then all of a partition\'s replicas are equivalent and they can either be ONLINE or OFFLINE. +2. If a system takes _both_ reads and writes but must ensure that writes go through only one partition, the states will be MASTER, SLAVE, and OFFLINE. Writes go through the MASTER and replicate to the SLAVEs. Optionally, reads can go through SLAVEs. + +Apart from defining the state for each partition, the transition path between states can be application specific. For example, in order to become MASTER it might be a requirement to first become a SLAVE. This ensures that if the SLAVE does not have the data as part of OFFLINE-SLAVE transition it can bootstrap data from other nodes in the system. + +Helix provides a way to configure an application-specific state machine along with constraints on each state. Along with constraints on STATE, Helix also provides a way to specify constraints on transitions. (More on this later.) + +``` + OFFLINE | SLAVE | MASTER + _____________________________ + | | | | +OFFLINE | N/A | SLAVE | SLAVE | + |__________|________|_________| + | | | | +SLAVE | OFFLINE | N/A | MASTER | + |__________|________|_________| + | | | | +MASTER | SLAVE | SLAVE | N/A | + |__________|________|_________| + +``` + + + +## Concepts + +The following terminologies are used in Helix to model resources following a state machine. + +* __IdealState__: The state in which we need the cluster to be in if all nodes are up and running. In other words, all state constraints are satisfied. +* __CurrentState__: The actual current state of each node in the cluster +* __ExternalView__: The combined view of the CurrentState of all nodes. + +The goal of Helix is always to make the CurrentState (and by extension, the ExternalView) of the system same as the IdealState. Some scenarios where this may not be true are: + +* Some or all nodes are down +* One or more nodes fail +* New nodes are added and the partitions need to be reassigned + +### IdealState + +Helix lets the application define the IdealState for each resource. It consists of: + +* A list of partitions, e.g. 64 +* Number of replicas for each partition, e.g. 3 +* The assigned node and state for each replica + +Example: + +* Partition-1, replica-1: Master, Node-1 +* Partition-1, replica-2: Slave, Node-2 +* Partition-1, replica-3: Slave, Node-3 +* ..... +* ..... +* Partition-p, replica-r: Slave, Node-n + +Helix comes with various algorithms to automatically assign the partitions to nodes. The default algorithm minimizes the number of shuffles that happen when new nodes are added to the system. + +### CurrentState + +Every participant in the cluster hosts one or more partitions of a resource. Each of the partitions has a state associated with it. + +Example Node-1 + +* Partition-1, Master +* Partition-2, Slave +* .... +* .... +* Partition-p, Slave + +### ExternalView + +External clients needs to know the state of each partition in the cluster and the Node hosting that partition. Helix provides one view of the system to Spectators as the ExternalView. The ExternalView is simply an aggregate of all node CurrentStates. + +* Partition-1, replica-1, Master, Node-1 +* Partition-1, replica-2, Slave, Node-2 +* Partition-1, replica-3, Slave, Node-3 +* ..... +* ..... +* Partition-p, replica-3, Slave, Node-n + +## Process Workflow + +Mode of operation in a cluster + +A node process can be one of the following: + +* Participant: The process registers itself in the cluster and acts on the messages received in its queue and updates the current state. Example: a storage node in a distributed database +* Spectator: The process is simply interested in the changes in the ExternalView. +* Controller: This process actively controls the cluster by reacting to changes in cluster state and sending state transition messages to Participants. + +### Participant Node Process + +* When the Participant starts up, it registers itself under __LiveInstances__ +* After registering, it waits for new __messages__ in the message queue +* When it receives a message, it will perform the required task as indicated in the message +* After the task is completed, depending on the task outcome it updates the CurrentState + +### Controller Process + +* Watches IdealState +* Notified when a Participant goes down, comes up, is added, or is removed. Watches the ephemeral LiveInstance ZNode and the CurrentState of each Participant in the cluster +* Triggers appropriate state transitions by sending messages to Participants + +### Spectator Process + +* When the process starts, it asks the Helix agent to be notified of changes in ExternalView +* Whenever it receives a notification, it reads the ExternalView and performs required duties + +### Interaction between the Controller, Participant and Spectator + +The following picture shows how Controllers, Participants and Spectators interact with each other. + + + +## Core Controller Algorithm + +* Get the IdealState and the CurrentState of active storage nodes from ZooKeeper +* Compute the delta between IdealState and CurrentState for each partition replica across all Participant nodes +* For each partition compute tasks based on the State Machine Table. It\'s possible to configure priority on the state Transition. For example, in case of MasterSlave: + * Attempt mastership transfer if possible without violating constraints + * Partition addition + * Partition drop +* Add the transition tasks in parallel if possible to the respective queue for each storage node (if the tasks added are mutually independent) +* If a transition task is dependent on another task being completed, do not add that task +* After any task is completed by a Participant, Controllers gets notified of the change and the algorithm is re-run until the CurrentState matches the IdealState. + +## Helix ZNode Layout + +Helix organizes ZNodes under the cluster name in multiple levels. + +The top level (under the cluster name) ZNodes are all Helix-defined and in upper case: + +* PROPERTYSTORE: application property store +* STATEMODELDEFES: state model definitions +* INSTANCES: instance runtime information including current state and messages +* CONFIGS: configurations +* IDEALSTATES: ideal states +* EXTERNALVIEW: external views +* LIVEINSTANCES: live instances +* CONTROLLER: cluster controller runtime information + +Under INSTANCES, there are runtime ZNodes for each instance. An instance organizes ZNodes as follows: + +* CURRENTSTATES + * sessionId + * resourceName +* ERRORS +* STATUSUPDATES +* MESSAGES +* HEALTHREPORT + +Under CONFIGS, there are different scopes of configurations: + +* RESOURCE: contains resource scope configurations +* CLUSTER: contains cluster scope configurations +* PARTICIPANT: contains participant scope configurations + +The following image shows an example of the Helix ZNode layout for a cluster named "test-cluster": + + http://git-wip-us.apache.org/repos/asf/helix/blob/39e0d3fb/website/src/site/markdown/ClientLibraries.md ---------------------------------------------------------------------- diff --git a/website/src/site/markdown/ClientLibraries.md b/website/src/site/markdown/ClientLibraries.md new file mode 100644 index 0000000..bcde42c --- /dev/null +++ b/website/src/site/markdown/ClientLibraries.md @@ -0,0 +1,36 @@ +<!--- +Licensed to the Apache Software Foundation (ASF) under one +or more contributor license agreements. See the NOTICE file +distributed with this work for additional information +regarding copyright ownership. The ASF licenses this file +to you under the Apache License, Version 2.0 (the +"License"); you may not use this file except in compliance +with the License. You may obtain a copy of the License at + + http://www.apache.org/licenses/LICENSE-2.0 + +Unless required by applicable law or agreed to in writing, +software distributed under the License is distributed on an +"AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY +KIND, either express or implied. See the License for the +specific language governing permissions and limitations +under the License. +--> + +<head> + <title>Client Libraries</title> +</head> + +Client Libraries +---------------------------- + +The following client libraries, in addition to the Helix Agent Java interface, are +available for Helix: + +### Clojure + +* `clj-helix` - https://github.com/Factual/clj-helix + +### Python + +* `pyhelix` - https://github.com/kanakb/pyhelix http://git-wip-us.apache.org/repos/asf/helix/blob/39e0d3fb/website/src/site/markdown/Concepts.md ---------------------------------------------------------------------- diff --git a/website/src/site/markdown/Concepts.md b/website/src/site/markdown/Concepts.md new file mode 100644 index 0000000..7df3ae3 --- /dev/null +++ b/website/src/site/markdown/Concepts.md @@ -0,0 +1,283 @@ +<!--- +Licensed to the Apache Software Foundation (ASF) under one +or more contributor license agreements. See the NOTICE file +distributed with this work for additional information +regarding copyright ownership. The ASF licenses this file +to you under the Apache License, Version 2.0 (the +"License"); you may not use this file except in compliance +with the License. You may obtain a copy of the License at + + http://www.apache.org/licenses/LICENSE-2.0 + +Unless required by applicable law or agreed to in writing, +software distributed under the License is distributed on an +"AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY +KIND, either express or implied. See the License for the +specific language governing permissions and limitations +under the License. +--> + +<head> + <title>Concepts</title> +</head> + +Concepts +---------------------------- + +Helix is based on the idea that a given task has the following attributes associated with it: + +* __Location__, e.g. it is available on Node N1 +* __State__, e.g. it is running, stopped etc. + +In Helix terminology, a task is referred to as a __resource__. + +### Ideal State + +An __IdealState__ allows one to map tasks to location and state. A standard way of expressing this in Helix is as follows: + +``` +"TASK_NAME" : { + "LOCATION" : "STATE" +} +``` + +Consider a simple case where you want to launch a resource \"myTask\" on node \"N1\". The IdealState for this can be expressed as follows: + +``` +{ + "id" : "MyTask", + "mapFields" : { + "myTask" : { + "N1" : "ONLINE", + } + } +} +``` + +### Partition + +If this task get too big to fit on one box, you might want to divide it into subtasks. Each subtask is referred to as a __partition__ in Helix. Let\'s say you want to divide the task into 3 subtasks/partitions, the IdealState can be changed as shown below. + +\"myTask_0\", \"myTask_1\", \"myTask_2\" are logical names representing the partitions of myTask. Each tasks runs on N1, N2 and N3 respectively. + +``` +{ + "id" : "myTask", + "simpleFields" : { + "NUM_PARTITIONS" : "3", + } + "mapFields" : { + "myTask_0" : { + "N1" : "ONLINE", + }, + "myTask_1" : { + "N2" : "ONLINE", + }, + "myTask_2" : { + "N3" : "ONLINE", + } + } +} +``` + +### Replica + +Partitioning allows one to split the data/task into multiple subparts. But let\'s say the request rate for each partition increases. The common solution is to have multiple copies for each partition. Helix refers to the copy of a partition as a __replica__. Adding a replica also increases the availability of the system during failures. One can see this methodology employed often in search systems. The index is divided into shards, and each shard has multiple copies. + +Let\'s say you want to add one additional replica for each task. The IdealState can simply be changed as shown below. + +For increasing the availability of the system, it\'s better to place the replica of a given partition on different nodes. + +``` +{ + "id" : "myIndex", + "simpleFields" : { + "NUM_PARTITIONS" : "3", + "REPLICAS" : "2", + }, + "mapFields" : { + "myIndex_0" : { + "N1" : "ONLINE", + "N2" : "ONLINE" + }, + "myIndex_1" : { + "N2" : "ONLINE", + "N3" : "ONLINE" + }, + "myIndex_2" : { + "N3" : "ONLINE", + "N1" : "ONLINE" + } + } +} +``` + +### State + +Now let\'s take a slightly more complicated scenario where a task represents a database. Unlike an index which is in general read-only, a database supports both reads and writes. Keeping the data consistent among the replicas is crucial in distributed data stores. One commonly applied technique is to assign one replica as the MASTER and remaining replicas as SLAVEs. All writes go to the MASTER and are then replicated to the SLAVE replicas. + +Helix allows one to assign different __states__ to each replica. Let\'s say you have two MySQL instances N1 and N2, where one will serve as MASTER and another as SLAVE. The IdealState can be changed to: + +``` +{ + "id" : "myDB", + "simpleFields" : { + "NUM_PARTITIONS" : "1", + "REPLICAS" : "2", + }, + "mapFields" : { + "myDB" : { + "N1" : "MASTER", + "N2" : "SLAVE", + } + } +} +``` + + +### State Machine and Transitions + +The IdealState allows one to exactly specify the desired state of the cluster. Given an IdealState, Helix takes up the responsibility of ensuring that the cluster reaches the IdealState. The Helix __controller__ reads the IdealState and then commands each Participant to take appropriate actions to move from one state to another until it matches the IdealState. These actions are referred to as __transitions__ in Helix. + +The next logical question is: how does the controller compute the transitions required to get to IdealState? This is where the __finite state machine__ concept comes in. Helix allows applications to plug in a finite state machine. A state machine consists of the following: + +* __State__: Describes the role of a replica +* __Transition__: An action that allows a replica to move from one state to another, thus changing its role. + +Here is an example of MasterSlave state machine: + +``` + OFFLINE | SLAVE | MASTER + _____________________________ + | | | | +OFFLINE | N/A | SLAVE | SLAVE | + |__________|________|_________| + | | | | +SLAVE | OFFLINE | N/A | MASTER | + |__________|________|_________| + | | | | +MASTER | SLAVE | SLAVE | N/A | + |__________|________|_________| + +``` + +Helix allows each resource to be associated with one state machine. This means you can have one resource as an index and another as a database in the same cluster. One can associate each resource with a state machine as follows: + +``` +{ + "id" : "myDB", + "simpleFields" : { + "NUM_PARTITIONS" : "1", + "REPLICAS" : "2", + "STATE_MODEL_DEF_REF" : "MasterSlave", + }, + "mapFields" : { + "myDB" : { + "N1" : "MASTER", + "N2" : "SLAVE", + } + } +} + +``` + +### Current State + +The __CurrentState__ of a resource simply represents its actual state at a participating node, a __participant__. In the below example: + +* INSTANCE_NAME: Unique name representing the process +* SESSION_ID: ID that is automatically assigned every time a process joins the cluster + +``` +{ + "id":"MyResource" + ,"simpleFields":{ + ,"SESSION_ID":"13d0e34675e0002" + ,"INSTANCE_NAME":"node1" + ,"STATE_MODEL_DEF":"MasterSlave" + } + ,"mapFields":{ + "MyResource_0":{ + "CURRENT_STATE":"SLAVE" + } + ,"MyResource_1":{ + "CURRENT_STATE":"MASTER" + } + ,"MyResource_2":{ + "CURRENT_STATE":"MASTER" + } + } +} +``` + +Each node in the cluster has its own CurrentState. + +### External View + +In order to communicate with the participants, external clients need to know the current state of each of the participants. The external clients are referred to as __spectators__. In order to make the life of spectator simple, Helix provides an ExternalView that is an aggregated view of the current state across all nodes. The ExternalView has a similar format as IdealState. + +``` +{ + "id":"MyResource", + "mapFields":{ + "MyResource_0":{ + "N1":"SLAVE", + "N2":"MASTER", + "N3":"OFFLINE" + }, + "MyResource_1":{ + "N1":"MASTER", + "N2":"SLAVE", + "N3":"ERROR" + }, + "MyResource_2":{ + "N1":"MASTER", + "N2":"SLAVE", + "N3":"SLAVE" + } + } +} +``` + +### Rebalancer + +The core component of Helix is the Controller which runs the Rebalancer algorithm on every cluster event. Cluster events can be one of the following: + +* Nodes start and/or stop +* Nodes experience soft and/or hard failures +* New nodes are added/removed +* Ideal state changes + +There are few more examples such as configuration changes, etc. The key takeaway: there are many ways to trigger the rebalancer. + +When a rebalancer is run it simply does the following: + +* Compares the ideal state and current state +* Computes the transitions required to reach the ideal state +* Issues the transitions to each participant + +The above steps happen for every change in the system. Once the current state matches the IdealState, the system is considered stable which implies \'IdealState = CurrentState = ExternalView\' + +### Dynamic IdealState + +One of the things that makes Helix powerful is that IdealState can be changed dynamically. This means one can listen to cluster events like node failures and dynamically change the ideal state. Helix will then take care of triggering the respective transitions in the system. + +Helix allows various granularities of control for adjusting the ideal state. Whenever a cluster event occurs, Helix can operate in one of three modes: + +* __FULL\_AUTO__: Helix will automatically determine the location and state of each replica based on constraints +* __SEMI\_AUTO__: Helix will take in a \"preference list\" representing the location each replica can live at, and automatically determine the state based on constraints +* __CUSTOMIZED__: Helix will take in a map of location to state and fire transitions to get the external view to match + +Helix comes with a few algorithms to automatically compute the IdealState based on the constraints. For example, if you have a resource of 3 partitions and 2 replicas, Helix can automatically compute the IdealState based on the nodes that are currently active. See the [tutorial](./0.6.4-docs/tutorial_rebalance.html) to find out more about various execution modes of Helix like FULL_AUTO, SEMI_AUTO and CUSTOMIZED. + + + + + + + + + + + + http://git-wip-us.apache.org/repos/asf/helix/blob/39e0d3fb/website/src/site/markdown/IRC.md ---------------------------------------------------------------------- diff --git a/website/src/site/markdown/IRC.md b/website/src/site/markdown/IRC.md new file mode 100644 index 0000000..6dd450f --- /dev/null +++ b/website/src/site/markdown/IRC.md @@ -0,0 +1,33 @@ +<!--- +Licensed to the Apache Software Foundation (ASF) under one +or more contributor license agreements. See the NOTICE file +distributed with this work for additional information +regarding copyright ownership. The ASF licenses this file +to you under the Apache License, Version 2.0 (the +"License"); you may not use this file except in compliance +with the License. You may obtain a copy of the License at + + http://www.apache.org/licenses/LICENSE-2.0 + +Unless required by applicable law or agreed to in writing, +software distributed under the License is distributed on an +"AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY +KIND, either express or implied. See the License for the +specific language governing permissions and limitations +under the License. +--> + +<head> + <title>IRC</title> +</head> + +IRC +--- + +We\'re often available on the ```#apachehelix``` channel on the ```chat.freenode.net``` server. You can use your favorite IRC client or the web client below to connect. + +### Web IRC Client + +To connect to our channel, just enter a username below. + +<iframe src="http://webchat.freenode.net/?channels=apachehelix"; style="width: 100%; height: 500px; border: none;" /> http://git-wip-us.apache.org/repos/asf/helix/blob/39e0d3fb/website/src/site/markdown/Publications.md ---------------------------------------------------------------------- diff --git a/website/src/site/markdown/Publications.md b/website/src/site/markdown/Publications.md new file mode 100644 index 0000000..e2f36b1 --- /dev/null +++ b/website/src/site/markdown/Publications.md @@ -0,0 +1,37 @@ +<!--- +Licensed to the Apache Software Foundation (ASF) under one +or more contributor license agreements. See the NOTICE file +distributed with this work for additional information +regarding copyright ownership. The ASF licenses this file +to you under the Apache License, Version 2.0 (the +"License"); you may not use this file except in compliance +with the License. You may obtain a copy of the License at + + http://www.apache.org/licenses/LICENSE-2.0 + +Unless required by applicable law or agreed to in writing, +software distributed under the License is distributed on an +"AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY +KIND, either express or implied. See the License for the +specific language governing permissions and limitations +under the License. +--> + +<head> + <title>Publications</title> +</head> + + +Publications +------------- + +* Untangling cluster management using Helix at [SOCC Oct 2012](http://www.socc2012.org/home/program) + - [paper](https://915bbc94-a-62cb3a1a-s-sites.googlegroups.com/site/acm2012socc/helix_onecol.pdf) + - [presentation](http://www.slideshare.net/KishoreGopalakrishna/helix-socc-v10final) +* Building distributed systems using Helix + - [presentation at RelateIQ](http://www.slideshare.net/KishoreGopalakrishna/helix-talk) + - [presentation at ApacheCon](http://www.slideshare.net/KishoreGopalakrishna/apache-con-buildingddsusinghelix) + - [presentation at VMWare](http://www.slideshare.net/KishoreGopalakrishna/apache-helix-presentation-at-vmware) +* Data driven testing: + - [short talk at LSPE meetup](http://www.slideshare.net/KishoreGopalakrishna/data-driven-testing) + - [paper DBTest 2013 acm SIGMOD:will be published on Jun 24, 2013](http://dbtest2013.soe.ucsc.edu/Program.htm) http://git-wip-us.apache.org/repos/asf/helix/blob/39e0d3fb/website/src/site/markdown/UseCases.md ---------------------------------------------------------------------- diff --git a/website/src/site/markdown/UseCases.md b/website/src/site/markdown/UseCases.md new file mode 100644 index 0000000..001b012 --- /dev/null +++ b/website/src/site/markdown/UseCases.md @@ -0,0 +1,113 @@ +<!--- +Licensed to the Apache Software Foundation (ASF) under one +or more contributor license agreements. See the NOTICE file +distributed with this work for additional information +regarding copyright ownership. The ASF licenses this file +to you under the Apache License, Version 2.0 (the +"License"); you may not use this file except in compliance +with the License. You may obtain a copy of the License at + + http://www.apache.org/licenses/LICENSE-2.0 + +Unless required by applicable law or agreed to in writing, +software distributed under the License is distributed on an +"AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY +KIND, either express or implied. See the License for the +specific language governing permissions and limitations +under the License. +--> + +<head> + <title>Use Cases</title> +</head> + + +# Use cases at LinkedIn + +At LinkedIn Helix framework is used to manage 3 distributed data systems which are quite different from each other. + +* Espresso +* Databus +* Search As A Service + +## Espresso + +Espresso is a distributed, timeline consistent, scal- able, document store that supports local secondary indexing and local transactions. +Espresso databases are horizontally partitioned into a number of partitions, with each partition having a certain number of replicas +distributed across the storage nodes. +Espresso designates one replica of each partition as master and the rest as slaves; only one master may exist for each partition at any time. +Espresso enforces timeline consistency where only the master of a partition can accept writes to its records, and all slaves receive and +apply the same writes through a replication stream. +For load balancing, both master and slave partitions are assigned evenly across all storage nodes. +For fault tolerance, it adds the constraint that no two replicas of the same partition may be located on the same node. + +### State model +Espresso follows a Master-Slave state model. A replica can be in Offline,Slave or Master state. +The state machine table describes the next state given the Current State, Final State + +``` + OFFLINE | SLAVE | MASTER + _____________________________ + | | | | +OFFLINE | N/A | SLAVE | SLAVE | + |__________|________|_________| + | | | | +SLAVE | OFFLINE | N/A | MASTER | + |__________|________|_________| + | | | | +MASTER | SLAVE | SLAVE | N/A | + |__________|________|_________| + +``` + +### Constraints +* Max number of replicas in Master state:1 +* Execution mode AUTO. i.e on node failure no new replicas will be created. Only the State of remaining replicas will be changed. +* Number of mastered partitions on each node must be approximately same. +* The above constraint must be satisfied when a node fails or a new node is added. +* When new nodes are added the number of partitions moved must be minimized. +* When new nodes are added the max number of OFFLINE-SLAVE transitions that can happen concurrently on new node is X. + +## Databus + +Databus is a change data capture (CDC) system that provides a common pipeline for transporting events +from LinkedIn primary databases to caches within various applications. +Databus deploys a cluster of relays that pull the change log from multiple databases and +let consumers subscribe to the change log stream. Each Databus relay connects to one or more database servers and +hosts a certain subset of databases (and partitions) from those database servers. + +For a large partitioned database (e.g. Espresso), the change log is consumed by a bank of consumers. +Each databus partition is assigned to a consumer such that partitions are evenly distributed across consumers and each partition is +assigned to exactly one consumer at a time. The set of consumers may grow over time, and consumers may leave the group due to planned or unplanned +outages. In these cases, partitions must be reassigned, while maintaining balance and the single consumer-per-partition invariant. + +### State model +Databus consumers follow a simple Offline-Online state model. +The state machine table describes the next state given the Current State, Final State + +<pre><code> + OFFLINE | ONLINE | + ___________________| + | | | +OFFLINE | N/A | ONLINE | + |__________|________| + | | | +ONLINE | OFFLINE | N/A | + |__________|________| + + +</code></pre> + + +## Search As A Service + +LinkedIn�s Search-as-a-service lets internal customers define custom indexes on a chosen dataset +and then makes those indexes searchable via a service API. The index service runs on a cluster of machines. +The index is broken into partitions and each partition has a configured number of replicas. +Each cluster server runs an instance of the Sensei system (an online index store) and hosts index partitions. +Each new indexing service gets assigned to a set of servers, and the partition replicas must be evenly distributed across those servers. + +### State model + + + http://git-wip-us.apache.org/repos/asf/helix/blob/39e0d3fb/website/src/site/markdown/index.md ---------------------------------------------------------------------- diff --git a/website/src/site/markdown/index.md b/website/src/site/markdown/index.md new file mode 100644 index 0000000..6edb053 --- /dev/null +++ b/website/src/site/markdown/index.md @@ -0,0 +1,113 @@ +<!--- +Licensed to the Apache Software Foundation (ASF) under one +or more contributor license agreements. See the NOTICE file +distributed with this work for additional information +regarding copyright ownership. The ASF licenses this file +to you under the Apache License, Version 2.0 (the +"License"); you may not use this file except in compliance +with the License. You may obtain a copy of the License at + + http://www.apache.org/licenses/LICENSE-2.0 + +Unless required by applicable law or agreed to in writing, +software distributed under the License is distributed on an +"AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY +KIND, either express or implied. See the License for the +specific language governing permissions and limitations +under the License. +--> + +<head> + <title>Home</title> +</head> + + +## Apache Helix + +Apache Helix is a generic _cluster management_ framework used for the automatic management of partitioned, replicated and distributed resources hosted on a cluster of nodes. __Helix automates reassignment of resources in the face of node failure and recovery, cluster expansion, and reconfiguration.__ + + +## What Is Cluster Management? + +To understand Helix, you first need to understand __cluster management__. A distributed system typically runs on multiple nodes for the following reasons: + +* scalability +* fault tolerance +* load balancing + +Each node performs one or more of the primary functions of the cluster, such as storing and serving data, producing and consuming data streams, and so on. __Once configured for your system, Helix acts as the global brain for the system__. It is designed to make decisions that cannot be made in isolation. Examples of such decisions that require global knowledge and coordination: + +* scheduling of maintainence tasks, such as backups, garbage collection, file consolidation, index rebuilds +* repartitioning of data or resources across the cluster +* informing dependent systems of changes so they can react appropriately to cluster changes +* throttling system tasks and changes + +While it is possible to integrate these functions into the distributed system, it complicates the code. Helix has abstracted common cluster management tasks, enabling the system builder to model the desired behavior with a declarative state model, and let Helix manage the coordination. __The result is less new code to write, and a robust, highly operable system__. + +## What does Helix provide? + +* Automatic assignment of resources and partitions to nodes +* Node failure detection and recovery +* Dynamic addition of resources +* Dynamic addition of nodes to the cluster +* Pluggable distributed state machine to manage the state of a resource via state transitions +* Automatic load balancing and throttling of transitions +* Optional pluggable rebalancing for user-defined assignment of resources and partitions + + +## Why Helix? + +Modeling a distributed system as a state machine with constraints on states and transitions has the following benefits: + +* Separates cluster management from the core functionality of the system. +* Allows a quick transformation from a single node system to an operable, distributed system. +* Increases simplicity: system components do not have to manage a global cluster. This division of labor makes it easier to build, debug, and maintain your system. + +--- + +### Join the Conversation + +[Bay Area Meetup Group](http://www.meetup.com/Building-distributed-systems-using-Apache-Helix-Meetup-group/) + +[`#apachehelix`](./IRC.html) + +[`[email protected]`](mailto:[email protected]) + +### News + +Apache Helix has two new releases: + +* [0.6.8](./0.6.8-docs/index.html) - A release that includes stability improvements. + + [\[Quick Start\]](./0.6.8-docs/Quickstart.html) [\[Release Notes\]](./releasenotes/release-0.6.8.html) + +* [0.7.1 (beta)](./0.7.1-docs/index.html) - A release that includes YARN integration, ad-hoc task management, and performant IPC. + + [\[Quick Start\]](./0.7.1-docs/Quickstart.html) [\[Release Notes\]](./releasenotes/release-0.7.1.html) + +### Download + +<a href="./0.6.8-docs/download.html" class="btn btn-primary btn-small">0.6.8</a> + +<a href="./0.7.1-docs/download.html" class="btn btn-primary btn-small">0.7.1 (beta)</a> + +### Maven Dependency + +``` +<dependency> + <groupId>org.apache.helix</groupId> + <artifactId>helix-core</artifactId> + <version>0.6.8</version> +</dependency> +``` + +### Building + +Requirements: JDK 1.6+, Maven 2.0.8+ + +``` +git clone https://git-wip-us.apache.org/repos/asf/helix.git +cd helix +git checkout helix-0.6.8 +mvn install package -DskipTests +``` http://git-wip-us.apache.org/repos/asf/helix/blob/39e0d3fb/website/src/site/markdown/involved/building.md ---------------------------------------------------------------------- diff --git a/website/src/site/markdown/involved/building.md b/website/src/site/markdown/involved/building.md new file mode 100644 index 0000000..96a0fae --- /dev/null +++ b/website/src/site/markdown/involved/building.md @@ -0,0 +1,34 @@ +<!--- +Licensed to the Apache Software Foundation (ASF) under one +or more contributor license agreements. See the NOTICE file +distributed with this work for additional information +regarding copyright ownership. The ASF licenses this file +to you under the Apache License, Version 2.0 (the +"License"); you may not use this file except in compliance +with the License. You may obtain a copy of the License at + + http://www.apache.org/licenses/LICENSE-2.0 + +Unless required by applicable law or agreed to in writing, +software distributed under the License is distributed on an +"AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY +KIND, either express or implied. See the License for the +specific language governing permissions and limitations +under the License. +--> + + +Building Apache Helix +-------------- + +First you need to install [Apache Maven](http://maven.apache.org) 2.0.8+. + +To install JARs locally: + +``` +mvn clean install (-DskipTests if you don't want to run tests) +``` + +### Contribution Guide + +If you are interested in contributing to Helix, [here](https://cwiki.apache.org/confluence/display/HELIX/Contributor+Workflow) is a guide. http://git-wip-us.apache.org/repos/asf/helix/blob/39e0d3fb/website/src/site/markdown/involved/contribdocs.md ---------------------------------------------------------------------- diff --git a/website/src/site/markdown/involved/contribdocs.md b/website/src/site/markdown/involved/contribdocs.md new file mode 100644 index 0000000..30c1800 --- /dev/null +++ b/website/src/site/markdown/involved/contribdocs.md @@ -0,0 +1,66 @@ +<!--- +Licensed to the Apache Software Foundation (ASF) under one +or more contributor license agreements. See the NOTICE file +distributed with this work for additional information +regarding copyright ownership. The ASF licenses this file +to you under the Apache License, Version 2.0 (the +"License"); you may not use this file except in compliance +with the License. You may obtain a copy of the License at + + http://www.apache.org/licenses/LICENSE-2.0 + +Unless required by applicable law or agreed to in writing, +software distributed under the License is distributed on an +"AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY +KIND, either express or implied. See the License for the +specific language governing permissions and limitations +under the License. +--> + +Improve this Website +-------------------- + +Learn something new about Helix that you think would benefit others? The source for this website is available for you to look at and edit! + +### Get the Code +``` +git clone https://git-wip-us.apache.org/repos/asf/helix.git +cd helix/website +``` + +### Make Changes + +The website is structured as follows: + +``` +website/ -- the root directory for the Helix website + src/site -- source files for all the top-level webpages + site.xml -- metadata for the top-level website + version-docs/ -- the root directory for the documentation for a given Helix version + src/site -- source files for documentation specific to the version + site.xml -- metadata for the release documentation + pom.xml -- Maven pom for the release documentation package + pom.xml -- parent Maven pom for the website + deploySite.sh -- script to deploy the website publicly (for committers) +``` + +### Build Locally + +To build the website, do the following: + +``` +mvn site +mvn site:stage +``` + +Then, the entire website will be placed in `target/staging`. If you have Python installed, this command will start a local web server on port 8000: + +``` +pushd target/staging; python -m SimpleHTTPServer; popd +``` + +### Submitting Changes + +Once satisfied with any new changes to the website, the standard [code contribution](https://cwiki.apache.org/confluence/display/HELIX/Contributor+Workflow) guidelines apply, including code review and submitting patches. + +If you\'re a Helix committer, you can run `deploySite.sh` to go live. http://git-wip-us.apache.org/repos/asf/helix/blob/39e0d3fb/website/src/site/markdown/sources.md ---------------------------------------------------------------------- diff --git a/website/src/site/markdown/sources.md b/website/src/site/markdown/sources.md new file mode 100644 index 0000000..0d5dd90 --- /dev/null +++ b/website/src/site/markdown/sources.md @@ -0,0 +1,54 @@ +<!--- +Licensed to the Apache Software Foundation (ASF) under one +or more contributor license agreements. See the NOTICE file +distributed with this work for additional information +regarding copyright ownership. The ASF licenses this file +to you under the Apache License, Version 2.0 (the +"License"); you may not use this file except in compliance +with the License. You may obtain a copy of the License at + + http://www.apache.org/licenses/LICENSE-2.0 + +Unless required by applicable law or agreed to in writing, +software distributed under the License is distributed on an +"AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY +KIND, either express or implied. See the License for the +specific language governing permissions and limitations +under the License. +--> + +<head> + <title>Source Repository</title> +</head> + +## Helix Source Repository + +### Overview + +This project uses [Git](http://git-scm.com/) to manage its source code. Instructions on Git can be found at [http://git-scm.com/documentation](http://git-scm.com/documentation). + +### Web Access + +The following is a link to the online source repository. + +[https://git-wip-us.apache.org/repos/asf?p=helix.git;a=summary](https://git-wip-us.apache.org/repos/asf?p=helix.git;a=summary) + +### Anonymous Access + +The source can be checked out anonymously from Git with this command (See [http://git-scm.com/docs/git-clone](http://git-scm.com/docs/git-clone)): + +``` +git clone https://git-wip-us.apache.org/repos/asf/helix.git +``` + +### Developer Access + +Only project developers can access the Git tree via this method (See [http://git-scm.com/docs/git-clone](http://git-scm.com/docs/git-clone)). + +``` +git clone https://git-wip-us.apache.org/repos/asf/helix.git +``` + +### Access from Behind a Firewall + +Refer to the documentation of the SCM used for more information about access behind a firewall. http://git-wip-us.apache.org/repos/asf/helix/blob/39e0d3fb/website/src/site/resources/.htaccess ---------------------------------------------------------------------- diff --git a/website/src/site/resources/.htaccess b/website/src/site/resources/.htaccess new file mode 100644 index 0000000..c6613b1 --- /dev/null +++ b/website/src/site/resources/.htaccess @@ -0,0 +1,30 @@ +# +# Licensed to the Apache Software Foundation (ASF) under one +# or more contributor license agreements. See the NOTICE file +# distributed with this work for additional information +# regarding copyright ownership. The ASF licenses this file +# to you under the Apache License, Version 2.0 (the +# "License"); you may not use this file except in compliance +# with the License. You may obtain a copy of the License at +# +# http://www.apache.org/licenses/LICENSE-2.0 +# +# Unless required by applicable law or agreed to in writing, +# software distributed under the License is distributed on an +# "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY +# KIND, either express or implied. See the License for the +# specific language governing permissions and limitations +# under the License. +# + +Redirect /download.html /download.cgi +Redirect /0.6.1-incubating-docs/download.html /0.6.1-incubating-docs/download.cgi +Redirect /0.6.2-incubating-docs/download.html /0.6.2-incubating-docs/download.cgi +Redirect /0.7.0-incubating-docs/download.html /0.7.0-incubating-docs/download.cgi +Redirect /0.6.3-docs/download.html /0.6.3-docs/download.cgi +Redirect /0.6.4-docs/download.html /0.6.4-docs/download.cgi +Redirect /0.6.5-docs/download.html /0.6.5-docs/download.cgi +Redirect /0.6.6-docs/download.html /0.6.6-docs/download.cgi +Redirect /0.6.7-docs/download.html /0.6.7-docs/download.cgi +Redirect /0.6.8-docs/download.html /0.6.8-docs/download.cgi +Redirect /0.7.1-docs/download.html /0.7.1-docs/download.cgi http://git-wip-us.apache.org/repos/asf/helix/blob/39e0d3fb/website/src/site/resources/download.cgi ---------------------------------------------------------------------- diff --git a/website/src/site/resources/download.cgi b/website/src/site/resources/download.cgi new file mode 100755 index 0000000..f9a0e30 --- /dev/null +++ b/website/src/site/resources/download.cgi @@ -0,0 +1,22 @@ +#!/bin/sh +# Just call the standard mirrors.cgi script. It will use download.html +# as the input template. +# +# Licensed to the Apache Software Foundation (ASF) under one +# or more contributor license agreements. See the NOTICE file +# distributed with this work for additional information +# regarding copyright ownership. The ASF licenses this file +# to you under the Apache License, Version 2.0 (the +# "License"); you may not use this file except in compliance +# with the License. You may obtain a copy of the License at +# +# http://www.apache.org/licenses/LICENSE-2.0 +# +# Unless required by applicable law or agreed to in writing, +# software distributed under the License is distributed on an +# "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY +# KIND, either express or implied. See the License for the +# specific language governing permissions and limitations +# under the License. +# +exec /www/www.apache.org/dyn/mirrors/mirrors.cgi $* http://git-wip-us.apache.org/repos/asf/helix/blob/39e0d3fb/website/src/site/resources/images/HELIX-components.png ---------------------------------------------------------------------- diff --git a/website/src/site/resources/images/HELIX-components.png b/website/src/site/resources/images/HELIX-components.png new file mode 100644 index 0000000..c0c35ae Binary files /dev/null and b/website/src/site/resources/images/HELIX-components.png differ http://git-wip-us.apache.org/repos/asf/helix/blob/39e0d3fb/website/src/site/resources/images/bootstrap_statemodel.gif ---------------------------------------------------------------------- diff --git a/website/src/site/resources/images/bootstrap_statemodel.gif b/website/src/site/resources/images/bootstrap_statemodel.gif new file mode 100644 index 0000000..b8f8a42 Binary files /dev/null and b/website/src/site/resources/images/bootstrap_statemodel.gif differ http://git-wip-us.apache.org/repos/asf/helix/blob/39e0d3fb/website/src/site/resources/images/feather_small.gif ---------------------------------------------------------------------- diff --git a/website/src/site/resources/images/feather_small.gif b/website/src/site/resources/images/feather_small.gif new file mode 100644 index 0000000..94f1892 Binary files /dev/null and b/website/src/site/resources/images/feather_small.gif differ http://git-wip-us.apache.org/repos/asf/helix/blob/39e0d3fb/website/src/site/resources/images/helix-architecture.png ---------------------------------------------------------------------- diff --git a/website/src/site/resources/images/helix-architecture.png b/website/src/site/resources/images/helix-architecture.png new file mode 100644 index 0000000..6f69a2d Binary files /dev/null and b/website/src/site/resources/images/helix-architecture.png differ http://git-wip-us.apache.org/repos/asf/helix/blob/39e0d3fb/website/src/site/resources/images/helix-logo.jpg ---------------------------------------------------------------------- diff --git a/website/src/site/resources/images/helix-logo.jpg b/website/src/site/resources/images/helix-logo.jpg new file mode 100644 index 0000000..6299014 Binary files /dev/null and b/website/src/site/resources/images/helix-logo.jpg differ http://git-wip-us.apache.org/repos/asf/helix/blob/39e0d3fb/website/src/site/resources/images/helix-znode-layout.png ---------------------------------------------------------------------- diff --git a/website/src/site/resources/images/helix-znode-layout.png b/website/src/site/resources/images/helix-znode-layout.png new file mode 100644 index 0000000..5bafc45 Binary files /dev/null and b/website/src/site/resources/images/helix-znode-layout.png differ http://git-wip-us.apache.org/repos/asf/helix/blob/39e0d3fb/website/src/site/resources/images/statemachine.png ---------------------------------------------------------------------- diff --git a/website/src/site/resources/images/statemachine.png b/website/src/site/resources/images/statemachine.png new file mode 100644 index 0000000..43d27ec Binary files /dev/null and b/website/src/site/resources/images/statemachine.png differ http://git-wip-us.apache.org/repos/asf/helix/blob/39e0d3fb/website/src/site/resources/images/system.png ---------------------------------------------------------------------- diff --git a/website/src/site/resources/images/system.png b/website/src/site/resources/images/system.png new file mode 100644 index 0000000..f8a05c8 Binary files /dev/null and b/website/src/site/resources/images/system.png differ http://git-wip-us.apache.org/repos/asf/helix/blob/39e0d3fb/website/src/site/site.xml ---------------------------------------------------------------------- diff --git a/website/src/site/site.xml b/website/src/site/site.xml new file mode 100644 index 0000000..1156dfb --- /dev/null +++ b/website/src/site/site.xml @@ -0,0 +1,164 @@ +<?xml version="1.0" encoding="ISO-8859-1"?> +<!-- + Licensed to the Apache Software Foundation (ASF) under one or more + contributor license agreements. See the NOTICE file distributed with + this work for additional information regarding copyright ownership. + The ASF licenses this file to You under the Apache License, Version 2.0 + (the "License"); you may not use this file except in compliance with + the License. You may obtain a copy of the License at + + http://www.apache.org/licenses/LICENSE-2.0 + + Unless required by applicable law or agreed to in writing, software + distributed under the License is distributed on an "AS IS" BASIS, + WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. + See the License for the specific language governing permissions and + limitations under the License. +--> +<project name="Apache Helix"> + <bannerLeft> + <src>images/helix-logo.jpg</src> + <href>http://helix.apache.org/</href> + </bannerLeft> + <bannerRight> + <src>images/feather_small.gif</src> + <href>http://www.apache.org/</href> + </bannerRight> + + <publishDate position="none"/> + <version position="none"/> + + <skin> + <groupId>lt.velykis.maven.skins</groupId> + <artifactId>reflow-maven-skin</artifactId> + <version>1.0.0</version> + </skin> + + <body> + + <head> + <script type="text/javascript"> + + var _gaq = _gaq || []; + _gaq.push(['_setAccount', 'UA-3211522-12']); + _gaq.push(['_trackPageview']); + + (function() { + var ga = document.createElement('script'); ga.type = 'text/javascript'; ga.async = true; + ga.src = ('https:' == document.location.protocol ? 'https://ssl' : 'http://www') + '.google-analytics.com/ga.js'; + var s = document.getElementsByTagName('script')[0]; s.parentNode.insertBefore(ga, s); + })(); + + </script> + + </head> + + <breadcrumbs position="left"> + <item name="Apache Helix" href="http://helix.apache.org/"/> + </breadcrumbs> + + <menu name="Learn"> + <item name="Core Concepts" href="./Concepts.html"/> + <item name="Architecture" href="./Architecture.html"/> + <item name="Publications" href="./Publications.html"/> + <item name="Client Libraries" href="./ClientLibraries.html"/> + </menu> + + <menu name="Documentation"> + <item name="0.6.8 (stable)" href="./0.6.8-docs/index.html"/> + <item name="0.7.1 (beta)" href="./0.7.1-docs/index.html"/> + <item name="0.6.7" href="./0.6.7-docs/index.html"/> + <item name="0.6.6" href="./0.6.6-docs/index.html"/> + <item name="0.6.5" href="./0.6.5-docs/index.html"/> + <item name="0.6.4" href="./0.6.4-docs/index.html"/> + <item name="0.6.3" href="./0.6.3-docs/index.html"/> + <item name="0.7.0-incubating (alpha)" href="./0.7.0-incubating-docs/index.html"/> + <item name="0.6.2-incubating" href="./0.6.2-incubating-docs/index.html"/> + <item name="0.6.1-incubating" href="./0.6.1-incubating-docs/index.html"/> + <item name="trunk" href="./trunk-docs/index.html"/> + </menu> + + <menu name="Helix 0.6.8"> + <item name="Documentation" href="./0.6.8-docs/index.html"/> + <item name="Quick Start" href="./0.6.8-docs/Quickstart.html"/> + <item name="Tutorial" href="./0.6.8-docs/Tutorial.html"/> + <item name="Download" href="./0.6.8-docs/download.html"/> + </menu> + + <menu name="Helix 0.7.1 (beta)"> + <item name="Documentation" href="./0.7.1-docs/index.html"/> + <item name="Quick Start" href="./0.7.1-docs/Quickstart.html"/> + <item name="Tutorial" href="./0.7.1-docs/Tutorial.html"/> + <item name="Download" href="./0.7.1-docs/download.html"/> + </menu> + + <menu name="Get Involved"> + <item name="IRC" href="./IRC.html"/> + <item name="Mailing Lists" href="mail-lists.html"/> + <item name="Issues" href="issue-tracking.html"/> + <item name="Team" href="team-list.html"/> + <item name="Sources" href="sources.html"/> + <item name="Continuous Integration" href="integration.html"/> + <item name="Building Guide" href="/involved/building.html"/> + <item name="Release Guide" href="/releasing.html"/> + <item name="Improve this Website" href="/involved/contribdocs.html"/> + </menu> +<!-- + <menu ref="reports" inherit="bottom"/> + <menu ref="modules" inherit="bottom"/> + +--> + <menu name="ASF"> + <item name="ASF Home" href="http://www.apache.org/"/> + <item name="License" href="http://www.apache.org/licenses/"/> + <item name="Sponsorship" href="http://www.apache.org/foundation/sponsorship.html"/> + <item name="Thanks" href="http://www.apache.org/foundation/thanks.html"/> + <item name="Security" href="http://www.apache.org/security/"/> + </menu> + <footer> + <div class="row span16"><div>Apache Helix, Apache, the Apache feather logo, and the Apache Helix project logos are trademarks of The Apache Software Foundation. + All other marks mentioned may be trademarks or registered trademarks of their respective owners.</div> + <a href="${project.url}/privacy-policy.html">Privacy Policy</a> + </div> + </footer> + + + </body> + + <custom> + <!--fluidoSkin> + <topBarEnabled>true</topBarEnabled> + <googleSearch></googleSearch> + <twitter> + <user>ApacheHelix</user> + <showUser>true</showUser> + <showFollowers>false</showFollowers> + </twitter> + <sideBarEnabled>true</sideBarEnabled> + </fluidoSkin--> + <reflowSkin> + <theme>bootswatch-cerulean</theme> + <highlightJs>false</highlightJs> + <brand> + <name>Apache Helix</name> + <href>http://helix.apache.org</href> + </brand> + <slogan>A cluster management framework for partitioned and replicated distributed resources</slogan> + <bottomNav> + <column>Learn</column> + <column>Documentation|Helix 0.6.8|Helix 0.7.1 (beta)</column> + <column>Get Involved</column> + <column>ASF</column> + </bottomNav> + <pages> + <index> + <sections> + <body /> + <sidebar /> + </sections> + </index> + </pages> + </reflowSkin> + </custom> + +</project> http://git-wip-us.apache.org/repos/asf/helix/blob/39e0d3fb/website/src/site/xdoc/download.xml.vm ---------------------------------------------------------------------- diff --git a/website/src/site/xdoc/download.xml.vm b/website/src/site/xdoc/download.xml.vm new file mode 100644 index 0000000..6566784 --- /dev/null +++ b/website/src/site/xdoc/download.xml.vm @@ -0,0 +1,248 @@ +<?xml version="1.0" encoding="UTF-8"?> +<!-- +Licensed to the Apache Software Foundation (ASF) under one +or more contributor license agreements. See the NOTICE file +distributed with this work for additional information +regarding copyright ownership. The ASF licenses this file +to you under the Apache License, Version 2.0 (the +"License"); you may not use this file except in compliance +with the License. You may obtain a copy of the License at + + http://www.apache.org/licenses/LICENSE-2.0 + +Unless required by applicable law or agreed to in writing, +software distributed under the License is distributed on an +"AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY +KIND, either express or implied. See the License for the +specific language governing permissions and limitations +under the License. + +--> +<document xmlns="http://maven.apache.org/XDOC/2.0"; xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"; + xsi:schemaLocation="http://maven.apache.org/XDOC/2.0 http://maven.apache.org/xsd/xdoc-2.0.xsd";> + + <properties> + <title>Apache Helix Downloads</title> + <author email="[email protected]">Apache Helix Documentation Team</author> + </properties> + + <body> + <div class="toc_container"> + <macro name="toc"> + <param name="class" value="toc"/> + </macro> + </div> + + <section name="Apache Helix Downloads"> + <p>Apache Helix artifacts are distributed in source and binary form under the terms of the + <a href="http://www.apache.org/licenses/LICENSE-2.0";>Apache License, Version 2.0</a>. + See the included <tt>LICENSE</tt> and <tt>NOTICE</tt> files included in each artifact for additional license + information. + </p> + <p>Use the links below to download a source distribution of Apache Helix. + It is good practice to <a href="#Verifying_Releases">verify the integrity</a> of the distribution files.</p> + </section> + + <section name="Current Release"> + <p>Release date: 06/19/2017 </p> + <p><a href="releasenotes/release-${currentRelease}.html">${currentRelease} Release notes</a></p> + <a name="mirror"/> + <subsection name="Mirror"> + + <p> + [if-any logo] + <a href="[link]"> + <img align="right" src="[logo]" border="0" + alt="logo"/> + </a> + [end] + The currently selected mirror is + <b>[preferred]</b>. + If you encounter a problem with this mirror, + please select another mirror. + If all mirrors are failing, there are + <i>backup</i> + mirrors + (at the end of the mirrors list) that should be available. + </p> + + <form action="[location]" method="get" id="SelectMirror" class="form-inline"> + Other mirrors: + <select name="Preferred" class="input-xlarge"> + [if-any http] + [for http] + <option value="[http]">[http]</option> + [end] + [end] + [if-any ftp] + [for ftp] + <option value="[ftp]">[ftp]</option> + [end] + [end] + [if-any backup] + [for backup] + <option value="[backup]">[backup] (backup)</option> + [end] + [end] + </select> + <input type="submit" value="Change" class="btn"/> + </form> + + <p> + You may also consult the + <a href="http://www.apache.org/mirrors/";>complete list of mirrors.</a> + </p> + + </subsection> + <subsection name="${currentRelease} Sources"> + <table> + <thead> + <tr> + <th>Artifact</th> + <th>Signatures</th> + <th>Hashes</th> + </tr> + </thead> + <tbody> + <tr> + <td> + <a href="[preferred]/helix/${currentRelease}/src/helix-${currentRelease}-src.zip">helix-${currentRelease}-src.zip</a> + </td> + <td> + <a href="http://www.apache.org/dist/helix/${currentRelease}/src/helix-${currentRelease}-src.zip.asc";>asc</a> + </td> + <td> + <a href="http://www.apache.org/dist/helix/${currentRelease}/src/helix-${currentRelease}-src.zip.md5";>md5</a> + <a href="http://www.apache.org/dist/helix/${currentRelease}/src/helix-${currentRelease}-src.zip.sha1";>sha1</a> + </td> + </tr> + </tbody> + </table> + </subsection> + <subsection name="${currentRelease} Binaries"> + <table> + <thead> + <tr> + <th>Artifact</th> + <th>Signatures</th> + <th>Hashes</th> + </tr> + </thead> + <tbody> + <tr> + <td> + <a href="[preferred]/helix/${currentRelease}/binaries/helix-core-${currentRelease}-pkg.tar">helix-core-${currentRelease}-pkg.tar</a> + </td> + <td> + <a href="http://www.apache.org/dist/helix/${currentRelease}/binaries/helix-core-${currentRelease}-pkg.tar.asc";>asc</a> + </td> + <td> + <a href="http://www.apache.org/dist/helix/${currentRelease}/binaries/helix-core-${currentRelease}-pkg.tar.md5";>md5</a> + <a href="http://www.apache.org/dist/helix/${currentRelease}/binaries/helix-core-${currentRelease}-pkg.tar.sha1";>sha1</a> + </td> + </tr> + <tr> + <td> + <a href="[preferred]/helix/${currentRelease}/binaries/helix-admin-webapp-${currentRelease}-pkg.tar">helix-admin-webapp-${currentRelease}-pkg.tar</a> + </td> + <td> + <a href="http://www.apache.org/dist/helix/${currentRelease}/binaries/helix-admin-webapp-${currentRelease}-pkg.tar.asc";>asc</a> + </td> + <td> + <a href="http://www.apache.org/dist/helix/${currentRelease}/binaries/helix-admin-webapp-${currentRelease}-pkg.tar.md5";>md5</a> + <a href="http://www.apache.org/dist/helix/${currentRelease}/binaries/helix-admin-webapp-${currentRelease}-pkg.tar.sha1";>sha1</a> + </td> + </tr> + <tr> + <td> + <a href="[preferred]/helix/${currentRelease}/binaries/helix-agent-${currentRelease}-pkg.tar">helix-agent-${currentRelease}-pkg.tar</a> + </td> + <td> + <a href="http://www.apache.org/dist/helix/${currentRelease}/binaries/helix-agent-${currentRelease}-pkg.tar.asc";>asc</a> + </td> + <td> + <a href="http://www.apache.org/dist/helix/${currentRelease}/binaries/helix-agent-${currentRelease}-pkg.tar.md5";>md5</a> + <a href="http://www.apache.org/dist/helix/${currentRelease}/binaries/helix-agent-${currentRelease}-pkg.tar.sha1";>sha1</a> + </td> + </tr> + <tr> + <td> + <a href="[preferred]/helix/${currentRelease}/binaries/helix-provisioning-${currentRelease}-pkg.tar">helix-provisioning-${currentRelease}-pkg.tar</a> + </td> + <td> + <a href="http://www.apache.org/dist/helix/${currentRelease}/binaries/helix-provisioning-${currentRelease}-pkg.tar.asc";>asc</a> + </td> + <td> + <a href="http://www.apache.org/dist/helix/${currentRelease}/binaries/helix-provisioning-${currentRelease}-pkg.tar.md5";>md5</a> + <a href="http://www.apache.org/dist/helix/${currentRelease}/binaries/helix-provisioning-${currentRelease}-pkg.tar.sha1";>sha1</a> + </td> + </tr> + <tr> + <td> + <a href="[preferred]/helix/${currentRelease}/binaries/helix-ipc-${currentRelease}-pkg.tar">helix-ipc-${currentRelease}-pkg.tar</a> + </td> + <td> + <a href="http://www.apache.org/dist/helix/${currentRelease}/binaries/helix-ipc-${currentRelease}-pkg.tar.asc";>asc</a> + </td> + <td> + <a href="http://www.apache.org/dist/helix/${currentRelease}/binaries/helix-ipc-${currentRelease}-pkg.tar.md5";>md5</a> + <a href="http://www.apache.org/dist/helix/${currentRelease}/binaries/helix-ipc-${currentRelease}-pkg.tar.sha1";>sha1</a> + </td> + </tr> + <tr> + <td> + <a href="[preferred]/helix/${currentRelease}/binaries/helix-examples-${currentRelease}-pkg.tar">helix-examples-${currentRelease}-pkg.tar</a> + </td> + <td> + <a href="http://www.apache.org/dist/helix/${currentRelease}/binaries/helix-examples-${currentRelease}-pkg.tar.asc";>asc</a> + </td> + <td> + <a href="http://www.apache.org/dist/helix/${currentRelease}/binaries/helix-examples-${currentRelease}-pkg.tar.md5";>md5</a> + <a href="http://www.apache.org/dist/helix/${currentRelease}/binaries/helix-examples-${currentRelease}-pkg.tar.sha1";>sha1</a> + </td> + </tr> + </tbody> + </table> + </subsection> + </section> + +<!-- <section name="Older Releases"> + </section>--> + + <section name="Verifying Releases"> + <p>It is essential that you verify the integrity of the downloaded file using the PGP signature (<tt>.asc</tt> file) or a hash (<tt>.md5</tt> or <tt>.sha1</tt> file). Please read <a href="http://www.apache.org/info/verification.html";>Verifying Apache Software Foundation Releases</a> for more information on why you should verify our releases.</p> + <p>The PGP signature can be verified using <a href="http://www.pgpi.org/";>PGP</a> or <a href="http://www.gnupg.org/";>GPG</a>. First download the <a href="http://www.apache.org/dist/helix/KEYS";>KEYS</a> as well as the <tt>*.asc</tt> signature files for the relevant distribution. Make sure you get these files from the main distribution site, rather than from a mirror. Then verify the signatures using one of the following sets of commands: + + <source>% pgpk -a KEYS +% pgpv downloaded_file.asc</source> + + or<br/> + + <source>% pgp -ka KEYS +% pgp downloaded_file.asc</source> + + or<br/> + + <source>% gpg --import KEYS +% gpg --verify downloaded_file.asc</source> + </p> + <p>Alternatively, you can verify the MD5 signature on the files. A Unix/Linux program called + <code>md5</code> or + <code>md5sum</code> is included in most distributions. It is also available as part of + <a href="http://www.gnu.org/software/textutils/textutils.html";>GNU Textutils</a>. + Windows users can get binary md5 programs from these (and likely other) places: + <ul> + <li> + <a href="http://www.md5summer.org/";>http://www.md5summer.org/</a> + </li> + <li> + <a href="http://www.fourmilab.ch/md5/";>http://www.fourmilab.ch/md5/</a> + </li> + <li> + <a href="http://www.pc-tools.net/win32/md5sums/";>http://www.pc-tools.net/win32/md5sums/</a> + </li> + </ul> + </p> + </section> + </body> +</document>
