Is there a way to execute command within a pod using Openshift Python Client?

[LiquIDMeowz]

Hi,

I'm trying to get ETCD Database size using the Python Client for OpenShift.
After authenticating against OpenShift, I can get the pod by name (for example v1_pod = dyn_client.resources.get(api_version='v1', kind='Pod', name='some_pod_name'), but how do I execute a command in the pod using the client?

I tried using subprocess.run, however due to a missing OC client on node side, the command fails.
My script looks like this and I'll create an image from it and run it as a daily CronJob:

`from kubernetes import client, config, dynamic
from openshift.dynamic import DynamicClient
from openshift.helper.userpassauth import OCPLoginConfiguration
import smtplib
from email.mime.text import MIMEText
from email.mime.multipart import MIMEMultipart
import urllib3
urllib3.disable_warnings()
import subprocess

Script checking for ETCD DB Size.

It will check for the cluster name and send info about current DB size of each ETCD Member.

Mail template

def send_mail(etcd_db):
mail_message = f"ETCD DB Sizes of {cname} Cluster -- {proc.stdout}"
msg = MIMEMultipart("alternative")
msg['From'] = ""
msg['To'] = ""
msg['Subject'] = f"ETCD DB Size for Cluster {cname}"
message_render = MIMEText(mail_message, "html")
msg.attach(message_render)
s = smtplib.SMTP('smtp.svcs.entsvcs.com', 25)
s.send_message(msg)

Authenticate against OCP

with open('/var/run/secrets/kubernetes.io/serviceaccount/token', 'r') as f:
token = f.readline().strip()
token_auth = dict(
api_key={'authorization': 'Bearer {}'.format(token)},
host='',
verify_ssl=False
)
configuration = client.Configuration()
for k, v in token_auth.items():
setattr(configuration, k, v)
k8s_client = client.ApiClient(configuration)
dyn_client = DynamicClient(k8s_client)

Get cluster name and set cname to = //

v1_name = dyn_client.resources.get(api_version='v1', kind='ConfigMap')
try:
cluster = v1_name.get(name='', namespace="").data.worker
cname = ""
except:
try:
cluster = v1_name.get(name='', namespace="").data.worker
cname = ""
except:
cluster = v1_name.get(name='', namespace="").data.worker
cname = ""

Check DB Size and send E-mail

etcd_db = "oc exec -c etcdctl -n openshift-etcd -- etcdctl endpoint status -w table --cluster | awk '{print $8, $9}' | tail -n 4"
proc = subprocess.run(etcd_db, shell=True, encoding='utf-8', stdout=subprocess.PIPE)
print(cname)
print(proc.stdout)
send_mail(etcd_db)`

Thank you!
LiquID

[bradmwilliams]

Hi @LiquIDMeowz,
Here is a script that should provide you a starting point for launching commands on a pod:

#!/usr/bin/python

import openshift as oc

if __name__ == '__main__':
    options = {
        'as': 'system:admin',
        'context': 'my_cluster_1',
    }

    with oc.client_host():
        with oc.timeout(60 * 5):
            with oc.options(options):
                with oc.project("openshift-etcd"):
                    pods = oc.selector("pods", labels={'app': 'etcd'}).objects()
                    print(f'Found: {len(pods)} pods')
                    result = pods[0].execute(cmd_to_exec=['etcdctl', 'endpoint', 'status', '--cluster', '-w', 'table'])
                    print(f'Result:\n{result.out()}')

[bradmwilliams]

Please note, based on your question, it sounds like you might actually be using the openshift-restclient-python library and the library associated with this repo openshift-client-python. They are not the same. My answer above would accomplish what you're looking for, but uses the openshift-client-python library.

[LiquIDMeowz]

@bradmwilliams Hi,

Thank you very much!