Authors:

avatar of Alex Lourie

Alex Lourie

Feature pages are design documents that developers have created while collaborating on oVirt.

Most of them are outdated, but provide historical design context.

They are not user documentation and should not be treated as such.

Documentation is available here.

Remote DB

Summary

Remote DB feature means working with a Postgres instance on a remote host.

Owner

  • Name: Alex Lourie (Alourie)

Current status

The code is developed and is a part of the upstream code.

Design and flow

Setup

  • During the engine-setup operation, user is asked to select ‘remote’ or ‘local’ installation. Default value ‘local’ is offered.

    • If entered ‘local’, the installation will continue and perform installation on the local machine.
    • If entered ‘remote’, the additional set of questions will be presented.
      • Additional questions include: DB Admin username, DB Port, Remote Db password and “Security usage” parameters.
  • Installation proceeds with normal flow.
  • During the normal flow, additional parameters (if entered by user) are used during DB creation and JBoss configuration.

DB configuration parameters are stored in ~/.pgpass file, including remote host, port and username/password.

JBoss configuration is stored in /usr/share/jboss-as/standalone/configuration/standalone.xml file.

  • If setup is rerun, the same parameters are used in “upgradeDb” function. Also, see next section for the upgrade logic.

Upgrade

  • During the upgrade, the DB connection values are received from ~/.pgpass file and used for connection.

  • The upgrade works as follows:

    • First, the packages are upgraded if necessary.
    • Before performing the DB upgrade, a backup is taken.
    • After the backup, the default DB (‘engine’) is renamed to ‘engine-<date>’
    • If renaming fails, yum rollback is performed, and user is notified about possible active connections.
    • If renaming succeeds, DB upgrade is started.
    • If upgrade fails, the renamed DB is removed and yum rollback is performed.
    • If upgrade succeeds, the ‘engine-<date>’ is renamed back to ‘engine’.

Cleanup

  • During the upgrade, the DB connection values are received from ~/.pgpass file and used for connection.
  • If DB drop fails user is notified about possible active connections.

Unattended (silent) installation

It is possible to use an answer file for the silent installation. The values for the RemoteDb are:

      DB_REMOTE_INSTALL=local
      DB_HOST=10.1.1.1
      DB_PORT=5433
      DB_ADMIN=remotedb_test
      DB_REMOTE_PASS=54321
      DB_SECURE_CONNECTION=no
      DB_LOCAL_PASS=admin!ad

To use with local installation, only DB_REMOTE_INSTALL=local and DB_LOCAL_PASS values are required.

To use with remote installation, use DB_REMOTE_INSTALL=remote and configure DB_HOST, DB_PORT, DB_ADMIN, DB_REMOTE_PASS and DB_SECURE_CONNECTION values as needed.

It is recommended to generate the answer file automatically:

engine-setup --gen-answer-file=<answer file full path>

…and then update its parameters accordingly with the installation requirements. After that, proceed with installation using the answer file:

engine-setup --answer-file=<answer file full path>