cloud-dbaas-ansible

Ansible-based DBaaS automation for Openstack projects.

The core architecture

Infrastructure

These playbooks are used to deploy and manage persistant-storage-based workloads:

• in order to provide high-availability and fencing, pacemaker is used ;
• in order to manage the workloads, nomad is used.

These playbooks also provide a control plane:

• consul & nomad masters.

Security

The user cannot login as administrator from outside of the cluster.

Database management

Provisionning

Each database is hosted on a dedicated pacemaker cluster. On the cluster side, a resource group is created:

• the cinder volume ;
• the mountpoints ;
• the floating IP ;
• the docker daemon ;
• the nomad agent.

Some nomad tasks are created:

• a service task to run the database engine ;
• a batch task to configure the database (users, schemas…).

Batchs

When the user wants to run some SQL administration queries, a nomad batch task is used.

Backups

Data are send to a Swift backend. We can use another cloud to be able to restart the database in case of disaster.

Upgrades

So as to use a minor engine’s upgrade, the current container is stopped, the new one is pulled and started.

When a data migration is required, a full backup is done in order to be restored using the new major release of the database engine.

Usage

The configuration files

# Copy the configuration files to a git-ops repo
export GITOPS=~/my-gitops-repo
export BRANCH=my-branch
cd $GITOPS
git checkout -b $BRANCH
cd -
mkdir -p $GITOPS/{etc,files}
cp example/*.yml $GITOPS/etc
cp example/*.txt $GITOPS/etc
# Create an openrc file
vi $GITOPS/files/openrc.sh
# Update the repo
cd $GITOPS
git add *
git commit -a -m "First commit to branch $BRANCH"
git push

The commands to run

export CLOUD_ANSIBLE=../cloud-dbaas-ansible
# Create the control-plane
ansible-playbook $CLOUD_ANSIBLE/control-plane.yml -e@etc/control_plane.yml

The HEAT stacks are deployed.

hosts.ini has been written and provides Nomad’s endpoint address.

# Create a PostgreSQL database
ansible-playbook $CLOUD_ANSIBLE/database.yml \
  -e type=postgresql \
  -e db_name=my-first-db \
  -e db_size_gb=10

my-first-db.yml has been written and contains how to connect against the database.

# Add the new database to gitops
git add my-first-db.yml
git commit my-first-db.yml -m "New DB my-first-db"
git push