It’s pretty easy to find how to decommission something in Ambari API.
For example, let’s decommission a datanode :
curl -u admin:admin -i -H 'X-Requested-By: ambari' -X POST -d '{
"RequestInfo":{
"context":"Decommission DataNodes dn1,dn2",
"command":"DECOMMISSION",
"parameters":{
"slave_type":"DATANODE",
"excluded_hosts":"dn1.example.com,dn2.example.com"
},
"operation_level":{
"level":"HOST_COMPONENT",
"cluster_name":"MY_CLUSTER"
}
},
"Requests/resource_filters":[
{
"service_name":"HDFS",
"component_name":"NAMENODE"
}
]
}' http://gw.example.com:8080/api/v1/clusters/MY_CLUSTER/requests
I then tried to recommission these datanodes using the “RECOMMISSION” command, and it failed.
The thing here is to change excluded_hosts (which is the list of hosts to be decommissioned), for included_hosts.
curl -u admin:admin -i -H 'X-Requested-By: ambari' -X POST -d '{
"RequestInfo":{
"context":"Recommission DataNodes dn1,dn2",
"command":"DECOMMISSION",
"parameters":{
"slave_type":"DATANODE",
"included_hosts":"dn1.example.com,dn2.example.com"
},
"operation_level":{
"level":"HOST_COMPONENT",
"cluster_name":"MY_CLUSTER"
}
},
"Requests/resource_filters":[
{
"service_name":"HDFS",
"component_name":"NAMENODE"
}
]
}' http://gw.example.com:8080/api/v1/clusters/MY_CLUSTER/requests
