References

A reference is a marker in the value of a configuration keyword, replaced during evaluation.

A reference is formatted as {<expression>}.

A reference can contain arithmetic evaluations.

An arithmetic evaluation can contain references.

References can be used to:

  • Abstract changing parts of a configuration, so this configuration can be used as a template Example: The object name, object id, the devices that hosts the data

  • Factorize information, so changing it is easier and safer Example: A projet name used to format the name of different resources (volume group, filesystem path, …)

  • Contextualize part of a configuration with information known to the agent Example: The cluster nodes, cluster dns ip addresses, …

Intra-Configuration References

The reference format is {[<section>.]<option>}, where

  • <section> is a configuration file section name

  • <option> is the option name in the pointed section.

If section is ommited, the referencing keyword’s section is implicitely used if the reference can be found locally, or the DEFAULT section is implicitely used.

Intra-Section References

These references can be used inside a configuration section and their evaluated value depends on the section.

Reference

Description

Node Configuration File

Service Configuration File

{rid}

The name of the section the reference is under

No

Yes

{rindex}

The part after the dash of the name of the section the reference is under

No

Yes

{<keyword>}

Reference to another keyword’s value inside the same section

Yes

Yes

Hard Coded References

Reference

Description

Node Configuration File

Service Configuration File

{nodename}

The running node fqdn

Yes

Yes

{short_nodename}

The running node base name (without domain)

Yes

Yes

{namespace}

The name of the hosting namespace

No

Yes

{kind}

The object kind, ie “svc”, “vol”, “sec”, “cfg”, “ccfg”

No

Yes

{name}

The object name

No

Yes

{path}

The object path, ie <namespace>/<kind>/<name>

No

Yes

{short_name}

The object base name (name with domain suffix stripped)

No

Yes

{fqdn}

The object fully qualified name, as registered in the cluster DNS, ie <name>.<namespace>.<kind>.<clustername>

No

Yes

{scaler_name}

The scaler name (because {name} resolves to the slice name)

No

Yes

{scaler_short_name}

The scaler base name (name with domain suffix stripped)

No

Yes

{id}

The object id

No

Yes

{safe://<id>}

Substitute the reference with the content of the safe file identified by <id>. Usually passwords or private keys. The content is cached locally so the collector dependency is loose.

Yes

Yes

{clustername}

The cluster.name node keyword value

Yes

Yes

{clusterid}

The cluster.id node keyword value

Yes

Yes

{clusternodes}

The cluster.nodes node keyword value

Yes

Yes

{clusterdrpnodes}

The cluster.drpnodes node keyword value

Yes

Yes

{dns}

The cluster.dns node keyword value (ip adressses)

Yes

Yes

{dnsnodes}

The cluster.dns node keyword value (resolved names)

Yes

Yes

{dnsuxsock}

The path to the dns thread unix socket

Yes

Yes

{dnsuxsockd}

The path to the directory hosting the dns thread unix socket

Yes

Yes

{collector_api}

The uri of the collector Rest API

Yes

Yes

{nodemgr}

The full path the the om node executable}

Yes

Yes

{svcmgr}

The full path the the svcmgr executable

Yes

Yes

{etc}

The agent etc/ directory path: /etc/opensvc/ for agents installed through the packages, /opt/opensvc/etc/ for an agent installed via git pull in /opt

Yes Yes

Yes Yes

{var}

The agent var/ directory path /var/lib/opensvc/ for agents installed through the packages, /opt/opensvc/var/ for an agent installed via git pull in /opt

Yes

Yes

{initd}

The object init directory path. ex: /etc/opensvc/etc/<name>.d

Yes

Yes

{private_var}

The object private directory under {var}

Yes

Yes

{<rid>.exposed_devs}

The whitespace-separated list of devpaths exposed by <rid>

No

Yes

{<rid>.exposed_devs[<n>]}

The <n>-th element of the list of devpaths exposed by <rid>

No

Yes

{<rid>.exposed_devs[#]}

The length of the list of devpaths exposed by <rid>

No

Yes

Deprecated references:

Reference

Description

Node Configuration File

Service Configuration File

{svcname}

Deprecated by {name}

No

Yes

{svcpath}

Deprecated by {path}

No

Yes

{short_svcname}

Deprecated by {short_name}

No

Yes

References and env Section

The env section can be used to store arbitrary factorized information to make available as references in other parts of the configuration.

Example:

[disk#0]
name = {id}
pvs = {env.devs}

[env]
devs = /dev/vdb

These values can be overridden when creating a new object from this configuration file or template,

  • Interactively om <path> create --config <template> --interactive

  • In the commandline om <path> create --config <template> --env devs=/dev/vdc