Hi,
I'm working on the Savanna HDP plugin, currently working on the capability to
scale a cluster (add hosts, remove hosts). The current approach to adding a
host is to:
1) Install the ambari agent on the host
2) start the ambari agent
3) register the host
4) add the required host components (based on the node group to which it is
being added)
5) install components (transition state from INIT to INSTALLED)
6) start the components (transition state from INSTALLED to STARTED)
I have a couple of questions regarding this approach:
1) Is it the ideal approach? Is there a more direct way of interacting with
ambari to provision a new host?
2) I am having an issue with the final step. During the invocation I get
the following error:
<html>
<head>
<meta http-equiv="Content-Type" content="text/html;charset=ISO-8859-1"/>
<title>Error 500 Invalid desired state for a client component</title>
</head>
<body>
<h2>HTTP ERROR: 500</h2>
<p>Problem accessing
/api/v1/clusters/my-cluster/hosts/my-cluster-slave-003.novalocal/host_components.
Reason:
<pre> Invalid desired state for a client component</pre></p>
<hr /><i><small>Powered by Jetty://</small></i>
The mix of components that are in the installed state is:
{
"href" :
"http://172.18.3.5:8080/api/v1/clusters/my-cluster/hosts/my-cluster-slave-003.novalocal/host_components?HostRoles/state=INSTALLED";,
"items" : [
{
"href" :
"http://172.18.3.5:8080/api/v1/clusters/my-cluster/hosts/my-cluster-slave-003.novalocal/host_components/DATANODE";,
"HostRoles" : {
"cluster_name" : "my-cluster",
"component_name" : "DATANODE",
"state" : "INSTALLED",
"host_name" : "my-cluster-slave-003.novalocal"
},
"host" : {
"href" :
"http://172.18.3.5:8080/api/v1/clusters/my-cluster/hosts/my-cluster-slave-003.novalocal";
}
},
{
"href" :
"http://172.18.3.5:8080/api/v1/clusters/my-cluster/hosts/my-cluster-slave-003.novalocal/host_components/MAPREDUCE_CLIENT";,
"HostRoles" : {
"cluster_name" : "my-cluster",
"component_name" : "MAPREDUCE_CLIENT",
"state" : "INSTALLED",
"host_name" : "my-cluster-slave-003.novalocal"
},
"host" : {
"href" :
"http://172.18.3.5:8080/api/v1/clusters/my-cluster/hosts/my-cluster-slave-003.novalocal";
}
},
{
"href" :
"http://172.18.3.5:8080/api/v1/clusters/my-cluster/hosts/my-cluster-slave-003.novalocal/host_components/HDFS_CLIENT";,
"HostRoles" : {
"cluster_name" : "my-cluster",
"component_name" : "HDFS_CLIENT",
"state" : "INSTALLED",
"host_name" : "my-cluster-slave-003.novalocal"
},
"host" : {
"href" :
"http://172.18.3.5:8080/api/v1/clusters/my-cluster/hosts/my-cluster-slave-003.novalocal";
}
},
{
"href" :
"http://172.18.3.5:8080/api/v1/clusters/my-cluster/hosts/my-cluster-slave-003.novalocal/host_components/GANGLIA_MONITOR";,
"HostRoles" : {
"cluster_name" : "my-cluster",
"component_name" : "GANGLIA_MONITOR",
"state" : "INSTALLED",
"host_name" : "my-cluster-slave-003.novalocal"
},
"host" : {
"href" :
"http://172.18.3.5:8080/api/v1/clusters/my-cluster/hosts/my-cluster-slave-003.novalocal";
}
},
{
"href" :
"http://172.18.3.5:8080/api/v1/clusters/my-cluster/hosts/my-cluster-slave-003.novalocal/host_components/TASKTRACKER";,
"HostRoles" : {
"cluster_name" : "my-cluster",
"component_name" : "TASKTRACKER",
"state" : "INSTALLED",
"host_name" : "my-cluster-slave-003.novalocal"
},
"host" : {
"href" :
"http://172.18.3.5:8080/api/v1/clusters/my-cluster/hosts/my-cluster-slave-003.novalocal";
}
}
]
}
So it appears that "CLIENT" components are not transitioned into the STARTED
state? Do I need to iterate thru these and avoid starting components with
CLIENT in their name?
-- Jon
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