Kolla’s strategy for upgrades is to never make a mess and to follow consistent patterns during deployment such that upgrades from one environment to the next are simple to automate.
Kolla implements a one command operation for upgrading an existing deployment consisting of a set of containers and configuration data to a new deployment.
Kolla uses the x.y.z semver nomenclature for naming versions. Kolla’s Liberty version is 1.0.0 and the Mitaka version is 2.0.0. The Kolla community commits to release z-stream updates every 45 days that resolve defects in the stable version in use and publish those images to the Docker Hub registry. To prevent confusion, the Kolla community recommends using an alpha identifier x.y.z.a where a represents any customization done on the part of the operator. For example, if an operator intends to modify one of the Docker files or the repos from the originals and build custom images for the Liberty version, the operator should start with version 1.0.0.0 and increase alpha for each release. Alpha tag usage is at discretion of the operator. The alpha identifier could be a number as recommended or a string of the operator’s choosing.
If the alpha identifier is not used, Kolla will deploy or upgrade using the version number information contained in the release. To customize the version number uncomment openstack_version in globals.yml and specify the version number desired.
For example, to deploy a custom built Liberty version built with the kolla-build --tag 1.0.0.0 operation, change globals.yml:
openstack_version: 1.0.0.0
Then run the command to deploy:
kolla-ansible deploy
If using Liberty and a custom alpha number of 0, and upgrading to 1, change globals.yml:
openstack_version: 1.0.0.1
Then run the command to upgrade:
kolla-ansible upgrade
Note
Varying degrees of success have been reported with upgrading the libvirt container with a running virtual machine in it. The libvirt upgrade still needs a bit more validation, but the Kolla community feels confident this mechanism can be used with the correct Docker graph driver.
Note
The Kolla community recommends the btrfs or aufs graph drivers for storing data as sometimes the LVM graph driver loses track of its reference counting and results in an unremovable container.
Note
Because of system technical limitations, upgrade of a libvirt container when using software emulation (virt_driver=qemu in nova.conf), does not work at all. This is acceptable because KVM is the recommended virtualization driver to use with Nova.
Kolla ships with several utilities intended to facilitate ease of operation.
tools/cleanup-containers can be used to remove deployed containers from the system. This can be useful when you want to do a new clean deployment. It will preserve the registry and the locally built images in the registry, but will remove all running Kolla containers from the local Docker daemon. It also removes the named volumes.
tools/cleanup-host can be used to remove remnants of network changes triggered on the Docker host when the neutron-agents containers are launched. This can be useful when you want to do a new clean deployment, particularly one changing the network topology.
tools/cleanup-images can be used to remove all Docker images built by Kolla from the local Docker cache.