DRBD is a distributed replicated storage system for the Linux platform. It is implemented as a kernel driver, several userspace management applications, and some shell scripts. DRBD is traditionally used in high availability (HA) computer clusters to provide a RAID 1 like configuration over a network.
Brooklyn-DRBD requires brooklyn-blockstore an open source addition to Brooklyn which enables provisioning of additional volumes for VMs, this should be installed as a bundle. Note that this is included by default in Cloudsoft AMP.
Brooklyn DRBD is a YAML blueprint for deployment and in-life management of a two node DRBD structure. Both DRBD 8.x and 9.x are supported and configurations of more than two nodes for DRBD 9 will be added in the near future.
| Config Key | Default | Description |
|---|---|---|
| drbd.version | 84 | The version of DRBD to use, (currently 84 or 90) |
| drbd.mountpoint | /mnt | The location that the DRBD filesystem will be mounted |
| drbd.filesystem | ext4 | The filesystem format of the DRBD volume |
| drive.capacity | 1 | The size in Gigabytes of the mirrored volume |
| drbd.nodes | 2 | The number of nodes (NB. 2 currently only supported) |
| drbd.skip.install | false | If we should skip the install of DRBD |
The main entity is called drbd-pair, this provisions a pair of DRBD nodes. You can then use nodeSpecification
and initialNodeSpecification to specify an entitySpec containing the blueprints you want on the nodes. An
example of this is shown in drbd.tomcat-example.bom. Finally propagatingSensor allows
you to specify a sensor which will be propagated back to the entity root.
services:
- type: drbd-pair
brooklyn.config:
propagatingSensor: $brooklyn:sensor("main.uri")
nodeSpecification:
$brooklyn:entitySpec:
- type: example-app
initialNodeSpecification:
$brooklyn:entitySpec:
- type: initial-example-app
DRBD 9+ supports the use of multiple secondaries, this will be implemented in the near future. Additionally in DRBD 8, multiple primaries are supported. This will require further development.