Multinode Deployment of Kolla¶

Deploy a registry¶

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 some type of registry is mandatory. Only one registry must be deployed, although HA features exist for registry services.

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.

Edit the /etc/kolla/globals.yml and add the following where 192.168.1.100 is the IP address of the machine and 5000 is the port where the registry is currently running:

docker_registry = 192.168.1.100:5000

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

cd kolla
tools/start-registry

The Docker registry can be configured as a pull through cache to proxy the official Kolla images hosted in Docker Hub. In order to configure the local registry as a pull through cache, in the host machine set the environment variable REGISTRY_PROXY_REMOTEURL to the URL for the repository on Docker Hub.

export REGISTRY_PROXY_REMOTEURL=https://registry-1.docker.io

Configure Docker on all nodes¶

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
INSECURE_REGISTRY="--insecure-registry 192.168.1.100:5000"

For Ubuntu, check whether its using upstart or systemd.

# stat /proc/1/exe
File: '/proc/1/exe' -> '/lib/systemd/systemd'

Edit /etc/default/docker and add:

# Ubuntu
DOCKER_OPTS="--insecure-registry 192.168.1.100:5000"

If Ubuntu is using systemd, additional settings needs to be configured. Copy Docker’s systemd unit file to /etc/systemd/system/ directory:

cp /lib/systemd/system/docker.service /etc/systemd/system/docker.service

Next, modify /etc/systemd/system/docker.service, add environmentFile variable and add $DOCKER_OPTS to the end of ExecStart in [Service] section:

# CentOS
[Service]
MountFlags=shared
EnvironmentFile=/etc/sysconfig/docker
ExecStart=
ExecStart=/usr/bin/docker daemon $INSECURE_REGISTRY

# Ubuntu
[Service]
MountFlags=shared
EnvironmentFile=-/etc/default/docker
ExecStart=
ExecStart=/usr/bin/docker daemon -H fd:// $DOCKER_OPTS

Restart Docker by executing the following commands:

# CentOS or Ubuntu with systemd
systemctl daemon-reload
systemctl restart docker

# Ubuntu with upstart or sysvinit
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-Ansible directory ansible/inventory/multinode. If Kolla-Ansible was installed with pip, it can be found in /usr/share/kolla-ansible.

Add the IP addresses or hostnames to a group and the services associated with that group will land on that host. IP addresses or hostnames must be added to the groups control, network, compute, monitoring and storage. Also, define additional behavioral inventory parameters such as ansible_ssh_user, ansible_become and ansible_private_key_file/ansible_ssh_pass which controls how ansible interacts with remote hosts.

# 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      ansible_ssh_user=<ssh-username> ansible_become=True ansible_private_key_file=<path/to/private-key-file>
192.168.122.24 ansible_ssh_user=<ssh-username> ansible_become=True ansible_private_key_file=<path/to/private-key-file>

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>

Run the deployment:

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