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 |
{#nodes} |
Number of nodes |
No |
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