Restart container within pod

Question

I have a pod test-1495806908-xn5jn with 2 containers  I d like to restart one of them called container-test  Is it possible to restart a single container within a pod and how  If not  how do I restart the pod   The pod was created using a deployment yaml with   kubectl create -f deployment yaml

User · Answer

kubectl exec -it POD NAME -c CONTAINER NAME bash - then kill 1   Assuming the container is run as root which is not recommended   In my case when I changed the application config  I had to reboot the container which was used in a sidecar pattern  I would kill the PID for the spring boot application which is owned by the docker user

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We use a pretty convenient command line to force re-deployment of fresh images on integration pod  We noticed that our alpine containers all run their  sustaining  command on PID 5  Therefore  sending it a SIGTERM signal takes the container down  imagePullPolicy being set to Always has the kubelet re-pull the latest image when it brings the container back   kubectl exec -i  pod name  -c  container-name  -- kill -15 5

User · Answer

Is it possible to restart a single container   Not through kubectl  although depending on the setup of your cluster you can  cheat  and docker kill the-sha-goes-here  which will cause kubelet to restart the  failed  container  assuming  of course  the restart policy for the Pod says that is what it should do      how do I restart the pod   That depends on how the Pod was created  but based on the Pod name you provided  it appears to be under the oversight of a ReplicaSet  so you can just kubectl delete pod test-1495806908-xn5jn and kubernetes will create a new one in its place  the new Pod will have a different name  so do not expect kubectl get pods to return test-1495806908-xn5jn ever again

User · Answer

I was playing around with ways to restart a container  What I found for me was this solution  Dockerfile      ENTRYPOINT    quot  app bootstrap sh quot      app bootstrap sh     bin bash  app startWhatEverYouActuallyWantToStart sh  amp  tail -f  dev null   Whenever I want to restart the container  I kill the process with tail -f  dev null which I find with kill -TERM  ps --ppid 1   grep tail   grep -v -e grep   awk   print  1     Following that command  all the processes except for the one with PID  1 will be killed and the entrypoint  in my case bootstrap sh will be executed  again   That s for the part  quot restart quot  - which is not really a restart but it does what you wish  in the end  For the part with limiting restarting the container named container-test you could pass on the container name to the container in question  as the container name would otherwise not be available inside the container  and then you can decide whether to do the above kill  That would be something like this in your deployment yaml      env      - name  YOUR CONTAINER NAME       value  container-test   app startWhatEverYouActuallyWantToStart sh     bin bash     CONDITION TO RESTART 0     if    quot  YOUR CONTAINER NAME quot      quot container-test quot  -a  CONDITION TO RESTART -eq 1    then     kill -TERM  ps --ppid 1   grep tail   grep -v -e grep   awk   print  1    fi

User · Answer

All the above answers have mentioned deleting the pod   but if you have many pods of the same service then it would be tedious to delete each one of them     Therefore  I propose the following solution  restart    1  Set scale to zero     kubectl scale deployment  lt  lt name gt  gt  --replicas 0 -n service    The above command will terminate all your pods with the name  lt  lt name gt  gt  2  To start the pod again  set the replicas to more than 0  kubectl scale deployment  lt  lt name gt  gt  --replicas 2 -n service   The above command will start your pods again with 2 replicas

User · Answer

There was an issue in coredns pod  I deleted such pod by  kubectl delete pod -n kube-system coredns-fb8b8dccf-8ggcf   Its pod will restart automatically

User · Answer

The whole reason for having kubernetes is so it manages the containers for you so you don t have to care so much about the lifecyle of the containers in the pod    Since you have a deployment setup that uses replica set  You can delete the pod using kubectl delete pod test-1495806908-xn5jn and kubernetes will manage the creation of a new pod with the 2 containers without any downtime  Trying to manually restart single containers in pods negates the whole benefits of kubernetes

User · Answer

There are cases when you want to restart a specific container instead of deleting the pod and letting Kubernetes recreate it   Doing a kubectl exec POD NAME -c CONTAINER NAME  sbin killall5 worked for me     I changed the command from reboot to  sbin killall5 based on the below recommendations

User · Answer

Killing the process specified in the Dockerfile s CMD   ENTRYPOINT works for me   The container restarts automatically   Rebooting was not allowed in my container  so I had to use this workaround

User · Answer

Both pod and container are ephemeral  try to use the following command to stop the specific container and the k8s cluster will restart a new container   kubectl exec -it  POD NAME  -c  CONTAINER NAME  --  bin sh -c  kill 1    This will send a SIGTERM signal to process 1  which is the main process running in the container  All other processes will be children of process 1  and will be terminated after process 1 exits  See the kill manpage for other signals you can send

[kubernetes] Restart container within pod

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