I am currently working on a bash script to reduce the time it takes for me to build the db for a project.
Currently I have several databases running in the same namespace and I want to extract only the specific pod name.
I run kubectl get pods
NAME READY STATUS RESTARTS AGE
elastic 1/1 Running 0 37h
mysql 1/1 Running 0 37h
Now I want to save one of the pod names.
I'm currently running this foo=$(kubectl get pods | grep -e "mysql")
and it returns mysql 1/1 Running 0 37h which is the expected results of the command. Now I just want to be able to extract the pod name as that variable so that I can pass it on at a later time.
This should work for you
foo=$(kubectl get pods | awk '{print $1}' | grep -e "mysql")
kubectl already allows you to extract only the names:
kubectl get pods -o=jsonpath='{range .items..metadata}{.name}{"\n"}{end}' | fgrep mysql
If I'm not mistaken, you merely needs to get only pod names to reuse these later.
The kubectl get --help provides a lot of good information on what you can achieve with just a kubectl without invoking the rest of the heavy artillery like awk, sed, etc.
List a single pod in JSON output format.
kubectl get -o json pod web-pod-13je7
List resource information in custom columns.
kubectl get pod test-pod -o
custom-columns=CONTAINER:.spec.containers[0].name,IMAGE:.spec.containers[0].image
Return only the phase value of the specified pod.
kubectl get -o template pod/web-pod-13je7 --template={{.status.phase}}
In this particular case I see at least 2 workarounds :
1) Custom columns. You can get virtually any output (and then you can grep/tr/awk if needed):
$ kubectl get pods --no-headers=true -o custom-columns=NAME_OF_MY_POD:.metadata.name
mmmysql-6fff9ffdbb-58x4b
mmmysql-6fff9ffdbb-72fj8
mmmysql-6fff9ffdbb-p76hx
mysql-tier2-86dbb787d9-r98qw
nginx-65f88748fd-s8mgc
2) jsonpath (the one #vault provided):
kubectl get pods -o=jsonpath='{.items..metadata.name}'
Hope that sheds light on options you have to choose from.
Let us know if that helps.
kubectl get pods | grep YOUR_POD_STARTING_NAME
For Example
kubectl get pods | grep mysql
Related
When I run the command kubectl get pods | grep "apisix", I get the following data
apisix-dev-78549978b7-pvh2v 1/1 Running 6 (4m19s ago) 8m14s
apisix-dev-dashboard-646df79bf-mwkpc 1/1 Running 6 (4m35s ago) 8m12s
apisix-dev-etcd-0 1/1 Running 0 8m12s
apisix-dev-etcd-1 1/1 Running 0 8m11s
apisix-dev-etcd-2 0/1 CrashLoopBackOff 4 (24s ago) 8m11s
apisix-dev-ingress-controller-58f7887759-28cm9 1/1 Running 0 8m11s
apisix-dev-ingress-controller-6cc65c7cb5-k6dx2 0/1 Init:0/1 0 8m9s
Is there any way to delete all the pods containing the word apisix instead of mentioning every pod name in kubectl delete command?
You can run a simple command:
kubectl delete pod $(kubectl get pod | grep apisix | awk '{print $1}')
A common way to select (and then, maybe delete) a set of Pods is via selector labels.
For example, assuming that a proper label app with value apisix exists:
# Find which Pods are selected (just to be sure)
kubectl get pod --selector=app=apisix
# Delete them (probably with --dry-run=client, if still unsure about what is selected)
kubectl delete pod --selector=app=apisix
Is there a way to get the pods that have status Running and also ready 1/1? This is what I tried so far:
kubectl get pod -l app=quarkus-jvm --field-selector=status.phase==Running
The command above returns also the pods that are not ready 0/1. I would like to get only one entry, the one with ready 1/1.
Thank you !
I have tested this on a playground
Before:
[node2 ~]$ kubectl get pods --field-selector=status.phase==Pending
nginx-deployment-66b6c48dd5-cctsd 0/1 Pending 0 8m29s
nginx-deployment-66b6c48dd5-hlhlp 0/1 Pending 0 8m29s
After
kubectl get pods --field-selector=status.phase==Pending | grep "66b6c48dd5-cctsd"
nginx-deployment-66b6c48dd5-cctsd 0/1 Pending 0 8m49s
The grep command is a way to filter content. You can try with this one command:
kubectl get pod -l app=quarkus-jvm --field-selector=status.phase==Running | grep "1/1"
I am writing a shell script for executing a pod for which the syntax is:
winpty kubectl --kubeconfig="C:\kubeconfig" -n namespace exec -it podname bash
This works fine but since podname is not stable and changes for every deployment so is there any alternative for this?
Thanks.
You can use normally $ kubectl exec command but define value for changing pod name.
Assuming that you have deployment and labeled pods: app=example, simply execute:
$ kubectl exec -it $(kubectl get pods -l app=example -o custom-columns=:metadata.name) -- bash
EDIT:
You can also execute:
POD_NAME = $(kubectl get pods -l app=example -o custom-columns=":metadata.name")
or
POD_NAME = $(kubectl get pods -l app=example -o jsonpath = "{. Items [0] .metadata.name}")
finally
$ winpty kubectl exec -ti $POD_NAME --bash
Make sure that you execute command in proper namespace - you can also add -n flag and define it.
You can use the following command:
kubectl -n <namespace> exec -it deploy/<deployment-name> -- bash
Add a service to your application:
As you know, pods are ephemeral; They come in and out of existence dynamically to ensure your application stays in compliance with your configuration. This behavior implements the scaling and self-healing aspects of kubernetes.
You application will consist of one or more pods that are accessible through a service , The application's service name and address does not change and so acts as the stable interface to reach your application.
This method works both if your application has one pod or many pods.
Does that help?
I am using kubernetes cluster to run dev environments for myself and other developers. I have written a few shell functions to help everyone deal with their pods without typing long kubectl commands by hand. For example, to get a prompt on one of the pods, my functions use the following
kubectl exec -it $(kubectl get pods --selector=run=${service} --field-selector=status.phase=Running -o jsonpath="{.items[*].metadata.name}") -- bash;
where $service is set to a service label I want to access, like postgres or redis or uwsgi.
Since these are development environments there is always one of each types of pods. The problem I am having is that if I delete a pod to make it pull a fresh image (all pods are managed by deployments, so if I delete a pod it will create a new one), for a while there are two pods, one shows as terminating and the other as running in kubectl get pods output. I want to make sure that the command above selects the pod that is running and not the one terminating. I thought --field-selector=status.phase=Running flag would do it, but it does not. Apparently even if the pod is in the process of terminating it still reports Running status in status.phase field. What can I use to filter out terminating pods?
Use this one
$ kubectl exec -it $(kubectl get pods --selector=run=${service} | grep "running" | awk '{print $1}') -- bash;
or
$ kubectl exec -it $(kubectl get pods --selector=run=${service} -o=jsonpath='{.items[?(#.status.phase==“Running”)].metadata.name}') -- bash;
Ref: https://kubernetes.io/docs/reference/kubectl/jsonpath/
Is there any alias we can make for all-namespace as kubectl don't recognise the command kubectl --all-namespaces or any kind of shortcut to minimize the typing of the whole command.
New in kubectl v1.14, you can use -A instead of --all-namespaces, eg:
kubectl get -A pod
(rejoice)
Is there any alias we can make for all-namespace
Based on this excellent SO answer you can create alias that inserts arguments between prefix and suffix like so:
alias kca='f(){ kubectl "$#" --all-namespaces -o wide; unset -f f; }; f'
and then use it regularly like so:
kca get nodes
kca get pods
kca get svc,sts,deploy,pvc,pv
etc..
Note: There is -o wide added for fun as well to get more detailed info about resources not normally namespaced like nodes and pv...