I need cluster-id using kubectl command.
root@vagrant-xenial64:~# kubectl get cm cluster-info -n kube-system -o jsonpath='{.data.cluster-config\.json}'
{
"cluster_id": "xxx",
"cluster_name": "prod-yyy-mmm",
"cluster_type": "rrr",
"cluster_pay_tier": "vvv",
"datacenter": "cse",
"account_id": "456777",
"created": "2018-06-32323dffdf:35:48+0000"
}
I need cluster-id of this particular json
root@vagrant-xenial64:~# kubectl get cm cluster-info -n kube-system -o jsonpath='{.data.cluster-config\.json.cluster_id}'
root@vagrant-xenial64:~#
Above command returns empty string. I tried many other combinations too
Your ConfigMap resource data-field contains a string which are interpreted as-is when you run jsonpath to select it via '{.data.cluster-config\.json}'. What i mean is that the shell you use will print it as JSON at stdout although it's stored differently in Kubernetes. If you run kubectl get cm cluster-info -n kube-system -o json and look at the data-field it might look something like this:
"data": {
"cluster-config.json": "{\n \"cluster_id\": \"xxx\",\n \"cluster_name\": \"prod-yyy-mmm\",\n \"cluster_type\": \"rrr\",\n \"cluster_pay_tier\": \"vvv\",\n \"datacenter\": \"cse\",\n \"account_id\": \"456777\",\n \"created\": \"2018-06-32323dffdf:35:48+0000\"\n}\n"
}
You won't be able to access the "fields" within that string with jsonpath since it's not actually part of the ConfigMap API resource fields.
You could try to use a second tool to fetch it though, using jq, a command-line JSON processor. This tool would interpret the output of jsonpath as JSON on the fly and parse it accordingly.
Example:
kubectl get cm cluster-info -n kube-system -o jsonpath='{.data.cluster-config\.json}' | jq '.cluster_id'
"xxx"If installing e.g. jq defeat any purposes i would recommend to use a combination of already available tools (assuming you're on Linux) like grep, awk and sed:
kubectl get cm cluster-info -n kube-system -o jsonpath='{.data.cluster-config\.json}' | grep cluster_id | awk '{ print $2 }' | sed -e 's/"//' -e 's/",//'
xxx