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https://issues.apache.org/jira/browse/TC-130?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel
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Ryan Durfey updated TC-130:
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Labels: configruation state_machine (was: )
Component/s: Traffic Ops API
Summary: Service Configuration Streamlining and Sequencing (was:
Streamlining TC management and operations sequences)
> Service Configuration Streamlining and Sequencing
> -------------------------------------------------
>
> Key: TC-130
> URL: https://issues.apache.org/jira/browse/TC-130
> Project: Traffic Control
> Issue Type: New Feature
> Components: Traffic Ops, Traffic Ops API, Traffic Router
> Reporter: Nir Sopher
> Labels: configruation, state_machine
>
> Hi,
> In order to further improve the simplicity and robustness of the control path
> for provisioning infrastructure and delivery services, we are currently
> considering ways to streamline management and operations.
> Currently, when applying changes in traffic-control that require the
> synchronization between the traffic-router and traffic-servers, the user
> should be conscious to do so in a certain order. Otherwise, "black holes" may
> be created. Furthermore, in some of the scenarios the user have to wait and
> verify that the configuration reached all traffic server before he may apply
> it to the traffic-router.
> The main use-cases we would like to address at this point are:
> * Assign servers to a Delivery-Service.
> For this operation, the configuration must first be applied to the added
> traffic servers, propagate, and only then applied to the traffic-router.
> * Remove servers assignment to a Delivery-Service.
> For this operation, the configuration must first be applied to the
> traffic-router, and only then to the traffic-servers.
> * Add a new delivery service.
> This is practically a private case of servers assignment to a
> delivery-service.
> * Delete a delivery service.
> This is practically a private case of servers assignment removal from a
> delivery-service.
> * Update settings that must be applied together on the traffic servers and
> the router.
> We would like to simplify the procedure, allowing the deployment of new
> configuration in a single operation, instead of doing it step by step.
> One solution can be based on the insight that deploying such configuration
> changes may be done by initially updating the traffic server with added
> functionality (e.g remap-rule), then updating the router, and lastly,
> removing old functionality from the traffic servers. Such a solution can be
> orchestrated by traffic-ops, probably without complicating other components.
> Other solutions may provide more flexibility, but would probably involve
> adding complexity to other components such as traffic-router.
> An example to such a solution, already under discussion in a mail tread (10x
> Eric:) may be based on the concept of a delivery-service configuration
> "generation" which would be an ordinal identifier for the a delivery service
> configuration. A "generation" changes whenever the remap rule changes or the
> consistent hash mapping of content to server changes (e.g. due to additional
> server assignment).
> In such a solution, each traffic-server may hold a single generation for each
> delivery service configuration, while traffic-router may hold a history of
> generations and know which server holds which configuration generation.
> This approach introduces a considerable flexibility. It allows configurations
> to be set one after the other with no need to wait between them.
> On the other hand, complicated algorithms for solving the issue may impose
> more risk to the network when applied, comparing to a simple "traffic-ops"
> orchestrated solution.
> Both approaches fit well with TC-129: Create TO API endpoint to queue all
> servers for a delivery service
> I'm not sure what is preferable from an operator point of view. I'm also not
> familiar with TC 3.0 "Config State Machine" solution to validate he different
> approaches against.
> Nir
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