How do I make this work?
[alan#stormfather-0be642-default-1 ~]$ kubectl exec -it my-pod-0 -- bash -c "/bin/bash && cd /tmp"
[root#my-pod-0 /]# pwd
/
Change directory first and then sh into it.
kubectl exec -it my-pod-0 -- bash -c "cd /tmp && /bin/bash"
Mohsin Amjad's answer is both simple and correct, if you are getting the
..."bash": executable file not found in $PATH...
error, this just means the container inside the pod does not have bash installed, instead try sh or other shells. I.e. something like:
kubectl exec -it my-pod-0 -- sh -c "cd /tmp && echo $0 $SHELL"
Related
I am trying to write a single line command to run a shell script which is inside the pod
getting a shell for a running container:
kubectl exec -it test-pod -c test-container -- /bin/bash
directory in the container:
cd test/bin
script inside the bin:
./backup.sh
how do I write all this in a single command?
Try:
kubectl exec -it test-pod -c test-container -- sh /full/path/to/the/backup.sh
Try:
kubectl exec -it test-pod -c test-container -- /bin/bash -c "/path/to/backup-script.sh"
After carrying out commands with "-c" option of bash, how can I make the terminal wait for input while preserving the environment?
Like CMD /K *** or pwsh -NoExit -Command ***.
From a comment by Cyrus:
You can achieve something similar by abusing the --rcfile option:
bash --rcfile <(echo "export PS1='> ' && ls")
From bash manpage:
--rcfile file
Execute commands from file instead of the system wide initialization file /etc/bash.bashrc and the standard personal initialization file ~/.bashrc if the shell is interactive
This is the answer I was looking for. Thank you!!
As an example of use, I use the following method to use the latest docker image with my preferred repository without building the image:
# Call bash in the container from bash
docker run --rm -it ubuntu:22.04 bash -c "bash --rcfile <(echo 'sed -i -E '\''s%^(deb(-src|)\s+)https?://(archive|security)\.ubuntu\.com/ubuntu/%\1http://mirrors.xtom.com/ubuntu/%'\'' /etc/apt/sources.list && apt update && FooBar=`date -uIs`')"
# ... from pwsh
docker run --rm -it ubuntu:22.04 bash -c "bash --rcfile <(echo 'sed -i -E '\''s%^(deb(-src|)\s+)https?://(archive|security)\.ubuntu\.com/ubuntu/%\1http://mirrors.xtom.com/ubuntu/%'\'' /etc/apt/sources.list && apt update && FooBar=``date -uIs``')"
# Call dash (BusyBox ash) in the container from bash
docker run --rm -it alpine:latest ash -c "ash -c 'export ENV=\$1;ash' -s <(echo 'sed -i -E '\''s%^https?://dl-cdn\.alpinelinux\.org/alpine/%https://ftp.udx.icscoe.jp/Linux/alpine/%'\'' /etc/apk/repositories && apk update && FooBar=`date -uIs`')"
# ... from pwsh
docker run --rm -it alpine:latest ash -c "ash -c 'export ENV=`$1;ash' -s <(echo 'sed -i -E '\''s%^https?://dl-cdn\.alpinelinux\.org/alpine/%https://ftp.udx.icscoe.jp/Linux/alpine/%'\'' /etc/apk/repositories && apk update && FooBar=``date -uIs``')"
I want to run a local script within Kubernetes pod and then set the output result to a linux variable
Here is what I tried:
# if I directly run -c "netstat -pnt |grep ssh", I get output assigned to $result:
cat check_tcp_conn.sh
#!/bin/bash
result=$(kubectl exec -ti <pod_name> -- /bin/bash -c "netstat -pnt |grep ssh")
echo "result is $result"
What I want is something like this:
#script to be called:
cat netstat_tcp_conn.sh
#!/bin/bash
netstat -pnt |grep ssh
#script to call netstat_tcp_conn.sh:
cat check_tcp_conn.sh
#!/bin/bash
result=$(kubectl exec -ti <pod_name> --
/bin/bash -c "./netstat_tcp_conn.sh)
echo "result is $result
the result showed result is /bin/bash: ./netstat_tcp_conn.sh: No such file or directory.
How can I let Kubernetes pod execute netstat_tcp_conn.sh which is at my local machine?
You can use following command to execute your script in your pod:
kubectl exec POD -- /bin/sh -c "`cat netstat_tcp_conn.sh`"
You can copy local files into pod using kubectl command like kubectl cp /tmp/foo :/tmp/
Then you can change its permission and make it executable and run it using kubectl exec.
I want to inject a few alias when execute docker exec command, otherwise I need to type such as alias ll='ls -l' everytime, so I made this a piece of code, but finally no aliases at all, anybody can help fixed this problem?
$ docker exec -itu root $(docker ps -l -q) bash -c "echo alias ll=\'ls -laF\' >> /alias.sh; \
shopt -s expand_aliases; source /alias.sh; exec bash"
root#c9ed5e18f77d:/# ll
bash: ll: command not found
root#c9ed5e18f77d:/# alias
root#c9ed5e18f77d:/# source /alias.sh
root#c9ed5e18f77d:/# alias
alias ll='ls -laF'
I have also tried this, it doesn't work either.
$ docker exec -itu root $(docker ps -l -q) bash -c "alias ll='ls -laF'; shopt -s expand_aliases; exec bash"
The docker container is debian-based, I can run this no problem, so I thought this is a trick about bash, please help.
$ docker exec -itu root $(docker ps -l -q) bash -c 'cd /opt; exec bash'
root#c9ed5e18f77d:/opt# pwd
/opt
root#c9ed5e18f77d:/opt#
This works:
# echo 1 and exit:
$ docker run -i -t image /bin/bash -c "echo 1"
1
# exit
# echo 1 and return shell in docker container:
$ docker run -i -t image /bin/bash -c "echo 1; /bin/bash"
1
root#4c064f2554de:/#
Question: How could I source a file into the shell? (this does not work)
$ docker run -i -t image /bin/bash -c "source <(curl -Ls git.io/apeepg) && /bin/bash"
# content from http://git.io/apeepg is sourced and shell is returned
root#4c064f2554de:/#
In my case, I use RUN source command (which will run using /bin/bash) in a Dockerfile to install nvm for node.js
Here is an example.
FROM ubuntu:14.04
RUN rm /bin/sh && ln -s /bin/bash /bin/sh
...
...
RUN source ~/.nvm/nvm.sh && nvm install 0.11.14
I wanted something similar, and expanding a bit on your idea, came up with the following:
docker run -ti --rm ubuntu \
bash -c 'exec /bin/bash --rcfile /dev/fd/1001 \
1002<&0 \
<<<$(echo PS1=it_worked: ) \
1001<&0 \
0<&1002'
--rcfile /dev/fd/1001 will use that file descriptor's contents instead of .bashrc
1002<&0 saves stdin
<<<$(echo PS1=it_worked: ) puts PS1=it_worked: on stdin
1001<&0 moves this stdin to fd 1001, which we use as rcfile
0<&1002 restores the stdin that we saved initially
You can use .bashrc in interactive containers:
RUN curl -O git.io/apeepg.sh && \
echo 'source apeepg.sh' >> ~/.bashrc
Then just run as usual with docker run -it --rm some/image bash.
Note that this will only work with interactive containers.
I don't think you can do this, at least not right now. What you could do is modify your image, and add the file you want to source, like so:
FROM image
ADD my-file /my-file
RUN ["source", "/my-file", "&&", "/bin/bash"]