BAND-AID for OOM issues with TripleO manual deployments

This post will explain how to fix OOM issues whe using TripleO.

If running free -m from your Undercloud or Overcloud nodes and getting some output like:

[asdf@fdsa]$ free -m
              total        used        free      shared  buff/cache   available
Mem:           7668        5555         219        1065        1893         663

And as in the example there is no reference pointing to the swap memory size and/or usage, you might not be using swap in your TripleO deployments, to enable it, just have to follow two steps.

First in the Undercloud, when deploying stacks you might find that heat-engine (4 workers) takes lot of RAM, in this case for specific usage peaks can be useful to have a swap file. In order to have this swap file enabled and used by the OS execute the following instructions in the Undercloud:

#Add a 4GB swap file to the Undercloud
sudo dd if=/dev/zero of=/swapfile bs=1024 count=4194304
sudo mkswap /swapfile
#Turn ON the swap file
sudo chmod 600 /swapfile
sudo swapon /swapfile
#Enable it on start
echo "/swapfile swap swap defaults 0 0" | sudo tee -a /etc/fstab

Also when deploying the Overcloud nodes the controller might face some RAM usage peaks, in which case, create a swap file in each Overcloud node by using an already existing “extraconfig swap” template.

To achieve this second part, we just need to use the environmental file that loads the swap template in the resource registry when deploying the overcloud.

Now, deploy your Overcloud as usual i.e.:

cd
openstack overcloud deploy \
--libvirt-type qemu \
--ntp-server pool.ntp.org \
--templates /home/stack/tripleo-heat-templates \
-e /home/stack/tripleo-heat-templates/overcloud-resource-registry-puppet.yaml \
-e /home/stack/tripleo-heat-templates/environments/enable-swap.yaml \
-e /home/stack/tripleo-heat-templates/environments/puppet-pacemaker.yaml

Bye bye OOM’s!!!!