Increase fs.inotify.max_user_watches in docker container

[RyanEwen]

Opening certain projects leads to this error. However I am not sure how to work around it within the container. I have tried simply mounting a modified /etc/sysctl.conf from my host but it doesn't seem to make a difference.

How can we increase this within the container?

[RyanEwen]

Arg.. appears I simply forgot to run sudo sysctl -p after editing the conf file. Will have to test if the conf file even needs to be mounted into the container at all now.

[ammario]

I believe there’s no concept of namespacing that value so it will just transparently share whatever is set on the host.

[RyanEwen]

Perfect. I just tested and the container inherits the setting without mounting in the conf file. Thanks :)

[perguth]

docker run -dit -p 8443:8443   -v "${HOME}/.code-server:/home/coder/.local/share/code-server"   -v "${PWD}:/home/coder/project" codercom/code-server --allow-http --no-auth
# ...
# 💻 Via a web terminal of `code-server`:
coder@6495fcb79cd7:~/project$ cat /proc/sys/fs/inotify/max_user_watches
8192
coder@6495fcb79cd7:~/project$ echo 'fs.inotify.max_user_watches=524288' | sudo tee -a /proc/sys/fs/inotify/max_user_watches
tee: /proc/sys/fs/inotify/max_user_watches: Read-only file system

😿

[ammario]

@perguth Docker mounts /proc as read-only since many of its knobs are global.

If you run that same command on the host, the container will transparently inherit the new setting.

[wellmsan]

I resolved by running the command on docker host machine:

echo fs.inotify.max_user_watches=524288 | sudo tee -a /etc/sysctl.conf

sudo sysctl -p

Success, thanks!

[maitrungduc1410]

The solution of @wellmsan works perfectly, but it misleading me at the first time because of "docker host machine". That means on your host machine, not inside docker container :)

[tcyfree]

Run the below command on docker host machine:
echo 524288| sudo dd of=/proc/sys/fs/inotify/max_user_watches

[doem97]

So there's nothing I can do within docker container? Somehow I can not get a root privilege on host, but I got root within docker container.

[ammario]

@doem97 if you're in a privileged container, you can set max_user_watches the same way you would on the host. For example, by running echo 524288 > /proc/sys/fs/inotify/max_user_watches.

It's possible that you're root within the container, but that user is mapped to an unprivileged one on the host. In such a case there's no way for you to change that setting.