Creating a pod in kubernetes which can run gnu screen - bash

Question

I am creating a long-lived jump to run inside of my kubernetes cluster. It uses an EBS volume for the home folder, holds important copies of my code, and gives me fast access for routine behavior. The problem is that I can't use GNU screen to create similarly long-lived sessions.
Here's my Dockerfile:
FROM ubuntu:zesty
ENV KUBECTL_VERSION=v1.7.6
RUN apt-get update && \
apt-get install -y \
htop vim sysstat \
build-essential make \
ruby ruby-dev rake \
postgresql-client libpq-dev \
curl wget \
python python-pip && \
pip install awscli && \
gem install --no-rdoc --no-ri bundler
RUN curl -LO https://storage.googleapis.com/kubernetes-release/release/$KUBECTL_VERSION/bin/linux/amd64/kubectl && \
chmod a+x kubectl && \
mv kubectl /usr/local/bin/kubectl
ADD dotfiles /root-dotfiles
ADD code /root-code
ADD docker-entrypoint.sh /docker-entrypoint.sh
And here's how I deploy it:
apiVersion: extensions/v1beta1
kind: Deployment
metadata:
labels:
app: doit
purpse: jumpbox
name: doit
namespace: default
spec:
replicas: 1
revisionHistoryLimit: 2
selector:
matchLabels:
app: doit
purpose: jumpbox
template:
metadata:
labels:
app: doit
purpose: jumpbox
spec:
containers:
- image: 123.dkr.ecr.eu-central-1.amazonaws.com/doit:latest
imagePullPolicy: Always
name: doit
command: ["sleep", "infinity"]
workingDir: /root
env:
- name: TERM
value: xterm
volumeMounts:
- mountPath: /root
subPath: root-homedir
name: doit-home
volumes:
- name: doit-home
persistentVolumeClaim:
claimName: doit-home
restartPolicy: Always
securityContext: {}
terminationGracePeriodSeconds: 1
But when I kubectl exec in to the container and try creating a screen:
root#doit-2561276907-kl2h6:~# screen -S asdf
Cannot open your terminal '' - please check.
I can work around this by doing:
root#doit-2561276907-kl2h6:~# script /dev/null
Script started, file is /dev/null
# bash
root#doit-2561276907-kl2h6:~# screen -S asdf
# now inside of the screen
Also, here's how I connect to the Pod:
function doit {
doit_pods=$(kubectl get pods -l 'app==doit' -o go-template --template '{{range .items}}{{.metadata.name}}{{"\n"}}{{end}}')
kubectl exec -it $doit_pods bash
}
So under the hood I am doing kubectl exec -it.
But I don't want all the users of this jumpbox instance to have to run script and switch back to bash. How can I create Pod which is already configured properly for screen?

Answer 1

I tried this with centos image it works, need to check the ubuntu image.
kubectl run -it screentest --image=centos -- bash
kubectl exec -it screentest-cbd49447f-286wq -- bash
yum -y install screen
screen
Tested this in ubuntu also, it works for me.
kubectl run -it ubuntuest --image=ubuntu -- bash
apt-get update -qq && apt-get install screen -y
screen
also tried with kubectl exec -it ubuntuest-78df75fbb-9sk6f -- bash it works.