LGTM Enterprise 1.20

Moving control pool components

Most LGTM Enterprise systems start with a single machine hosting all the components for the control pool. These components initially store their data in the default control pool data directory: /var/lib/lgtm.

As the system grows, you may want to move some components onto dedicated machines, for example, the two main storage components: the file store and the database. You may also wish to move the control pool data directory.

You can relocate individual components as follows:

  1. Take down LGTM using lgtm-down.
  2. Back up LGTM using your normal method.
  3. Update the cluster configuration:
    1. Edit the lgtm-cluster-config.yml file and specify the new hosts for the components you want to move, and/or change the data_path.
    2. Regenerate service configurations using lgtm-config-gen.jar.
    3. Deploy the new service configurations to all machines in the control pool, including the new host machines.
  4. Restore the components you want to move to the new host machines and/or move the control data directory.
  5. Bring LGTM back up using lgtm-up.
  6. Check that everything is working as expected. For example, check that you can log in as a user, view data for a project, and run a simple query.
  7. Delete any unwanted data from the original location for the components that you moved.

For more detailed information about the processes outlined in these steps, see:

Example

A system is initially set up with the control pool hosted on a single machine. As the system expands, the configuration is updated to change: the location of the control pool data directory, and the host machines for the database and file store. This is an excerpt from the updated lgtm-cluster-config.yml file, with the changes highlighted:

data_path: "/lgtm/control-pool/data"

coordinator:

  hostname: "lgtm"

database:

  hostname: "lgtm-db"

file_storage:

  hostname: "lgtm-files"

queue:

  hostname: "lgtm"

search:

  hostname: "lgtm"

Related topicsRelated topics