Spacewalk configuration using Vagrant, Saltstack, pgpool-II and Postgresql

This is an example of (semi)automatic configuration of Spacewalk nightly with Postgresql in high availability mode using pgpool-II.

The configuration is done using Vagrant + Saltstack

General setup

The setup is composed of two machines:

• app (192.168.99.2) - runs both Spacewalk and Postgresql master node
• dbslave (192.168.99.3) - runs the Postgresql slave

This is done only for the sake of simplicity. A more realistic setup would probably deploy the Postgresql master on it's own machine.

Also the pgpool setup is pretty basic. In a production setup you would probably want to have HA also for pgpool itself.

In case pgpool becomes a bottleneck a better alternative would be pgbouncer for the connection pooling part and pgpool for failover.

Again, to keep things simple, SaltStack is configured in masterless mode.

Postgresql setup

The idea is to use streaming replication (asynchronous) to keep the two database nodes in sync.

Since Postgresql does not implement any automatic failover, this has to be done using a third party tool (pgpool-II).

Spacewalk is configured to connect to pgpool. This way in the event of a failover, the application will not need to be reconfigured. pgpool will promote the replica and will switch over automatically.

How to get started

$ git clone https://github.com/mateiw/vagrant-spacewalk-pg

1. Start both machines:

$ vagrant up

2. Setup Postresql, pgpool and Spacewalk on app machine

Automatic provisioning is turned off by default. After the machines start, log into app machine and run the following as root (password for both root and vagrant user is vagrant):

# salt-call state.highstate

This should set up Postresql, pgpool and Spacewalk.

Alternatively, if you prefer to do it step by step, you can do the following on the app machine:

Install and configure Postgresql:

# salt-call state.sls postgres

Install and configure pgpool-II:

# salt-call state.sls pgpool

And finally install Spacewalk:

# salt-call state.sls spacewalk

3. Setup Postresql replica on dbslave

Now that the first node is up and running, log into dbslave and do the following:

# salt-call state.highstate

This should set up Postgresql and configure it as a replica of app.

4. Generate ssh keys for the failover script

The pgpool failover script needs to be able to log into dbslave from app and create the trigger file. Therefore we need to generate and copy ssh keys needed for password less login. This can be done only once both machines are up and the postgres user has been created.

On app do:

# salt-call state.sls ssh

5. Open Spacewalk in browser

Finally, you should have everything set up. Open in the browser https://localhost and you should be greeted by the Spacewalk GUI.

6. TODO

• change Vagrant file to use a libvirt box.