Jenkins on Docker - Free Swap Space 0

I've noticed that my master node on Jenkins shows

free swap space: 0 B

So I added a swap file as described here.

But this has no effect. What am I doing wrong?

Solution 1:

Run the following command to see if your host has a swap file configured:

free|grep -i Swap
Swap:            0          0          0

If you get "Swap: 0 0 0" like you see above your host has no swap configured.

Configure a swap file on your host:

dd if=/dev/zero of=swapfile bs=1M count=1K
mkswap swapfile
sudo chown root:root swapfile
sudo chmod 600 swapfile
sudo swapon swapfile

Verify your swap is configured:

free|grep -i Swap
Swap:      1048572          0    1048572

Good, we have a swap on the host.

Run your Jenkins docker by typing:

docker run --privileged -p 8080:8080 --name jenkins -p 50000:50000 jenkins

Notice you must run the docker in privileged mode.

When you run your Jenkins docker in privileged mode the host's swap will be available inside the docker, so your Jenkins master will have a working swap.

If your host already has a working swap in place, all you will need to do is run the Jenkins docker in privileged mode.