multinode.rst

Multinode Deployment of Kolla

Deploy a registry (required for multinode)

A Docker registry is a locally hosted registry that replaces the need to pull from the Docker Hub to get images. Kolla can function with or without a local registry, however for a multinode deployment a registry is required.

The Docker registry prior to version 2.3 has extremely bad performance because all container data is pushed for every image rather than taking advantage of Docker layering to optimize push operations. For more information reference pokey registry.

The Kolla community recommends using registry 2.3 or later. To deploy registry 2.3 do the following:

docker run -d -p 4000:5000 --restart=always --name registry registry:2

Note: Kolla looks for the Docker registry to use port 4000. (Docker default is port 5000)

After starting the registry, it is necessary to instruct Docker that it will be communicating with an insecure registry. To enable insecure registry communication on CentOS, modify the /etc/sysconfig/docker file to contain the following where 192.168.1.100 is the IP address of the machine where the registry is currently running:

# CentOS
other_args="--insecure-registry 192.168.1.100:4000"

For Ubuntu, edit /etc/default/docker and add:

# Ubuntu
DOCKER_OPTS="--insecure-registry 192.168.1.100:4000"

Docker Inc's packaged version of docker-engine for CentOS is defective and does not read the other_args configuration options from /etc/sysconfig/docker. To rectify this problem, ensure the following lines appear in the drop-in unit file at /etc/systemd/system/docker.service.d/kolla.conf:

# CentOS
[Service]
EnvironmentFile=/etc/sysconfig/docker
# It's necessary to clear ExecStart before attempting to override it
# or systemd will complain that it is defined more than once.
ExecStart=/usr/bin/docker daemon -H fd:// $other_args

And restart docker by executing the following commands:

# CentOS
systemctl daemon-reload
systemctl stop docker
systemctl start docker

# Ubuntu
sudo service docker restart

Edit the Inventory File

The ansible inventory file contains all the information needed to determine what services will land on which hosts. Edit the inventory file in the kolla directory ansible/inventory/multinode or if kolla was installed with pip, it can be found in /usr/share/kolla.

Add the ip addresses or hostnames to a group and the services associated with that group will land on that host:

# These initial groups are the only groups required to be modified. The
# additional groups are for more control of the environment.
[control]
# These hostname must be resolvable from your deployment host
control01
192.168.122.24

For more advanced roles, the operator can edit which services will be associated in with each group. Keep in mind that some services have to be grouped together and changing these around can break your deployment:

[kibana:children]
control

[elasticsearch:children]
control

[haproxy:children]
network

Deploying Kolla

First, check that the deployment targets are in a state where Kolla may deploy to them:

kolla-ansible prechecks -i <path/to/multinode/inventory/file>

For additional environment setup see the :ref:`deploying-kolla`.

Run the deployment:

kolla-ansible deploy -i <path/to/multinode/inventory/file>