setting key "vm.overcommit_memory": Read-only file system

[CybotTM]

sysctl vm.overcommit_memory=1
sysctl: setting key "vm.overcommit_memory": Read-only file system

see redis/docker-library-redis#19

[openfirmware]

Thanks for the heads up, I am taking a look at the cause.

[openfirmware]

It appears that /proc is read-only (docker#5703), and sysctl cannot edit the vm overcommit memory setting unless docker runs the container with the --privileged setting (source). This does change the value on the docker host as well.

This leaves three options.

1. Enable sysctl vm.overcommit_memory=1 on the docker host and it will apply to all running containers, including docker-redis.
2. Run docker-redis with --privileged, thus enabling vm.overcommit_memory for the docker host and all other containers. I do not recommend this as it is not obvious that the container made a change to your docker host.
3. Run docker-redis as-is and let Redis run without vm.overcommit_memory.

I will update the README to note this limitation.

[CVirus]

Enabling sysctl vm.overcommit_memory=1 on the docker host will NOT be inherited by the running containers :-(

EDIT1: Yes it will inherit.
EDIT2: It won't inherit on some OS configurations/machines.. still investigating.
EDIT3: Final findings .. overcommit_memory is inherited in all cases (my bad) .. somaxconn is inherited only when the container runs in host networking mode.

[Mehonoshin]

Hey, folks. Has anyone solved this issue?

[0xO0O0]

anyone at all?

[openfirmware]

I checked with Docker 17.03.1-ce today and option #1 I mentioned above seems to work on Ubuntu 14.04.5 LTS host:

host# sysctl vm.overcommit_memory
vm.overcommit_memory = 0
host# docker run -it --rm openfirmware/redis sysctl vm.overcommit_memory
vm.overcommit_memory = 0
host# sysctl vm.overcommit_memory=1
vm.overcommit_memory = 1
host# sysctl vm.overcommit_memory
vm.overcommit_memory = 0
host# docker run -it --rm openfirmware/redis sysctl vm.overcommit_memory
vm.overcommit_memory = 1

Option #2 doesn't work for me though. Let me know if that doesn't work for you.