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The case for hidden linkbacks

In several distributions, it is common for system scripts to try to operate on all files in a directory to accomplish a task. For example, RedHat tries to bring up every interface matching /etc/sysconfig/network-scripts/ifcfg-* at boot time.

If a LINKBACK is defined for /etc/sysconfig/network-scripts/ifcfg-eth0, the glob above will match all of the linkback targets for that file, including ifcfg-eth0.default and all node-specific versions of the file. The system script then tries to bring up the interface several times with potentially different configurations. This creates many problems, which could result in losing all static configurations.

For such cases it is desirable to `hide' (with the LINKBACK -h flag) all linkback targets so that the system scripts still function correctly.

When a linkback is hidden, all linkback targets will have a '.' pre-pended to the name, so ifcfg-eth0.default, when hidden, will become .ifcfg-eth0.default. Remember that all variants of the file also will need to be hidden. If you want a NODE-specific version of ifcfg-eth0 for admin1, the file .ifcfg-eth0.admin1 needs to be created to hold the configuration.

Note: Hidden LINKBACK directives only apply to CLASS, NODE, and PROPERTY specific linkback targets.

The mk-sysimage script transitions the .default file between hidden and un-hidden according to the configuration, but it does not alter any other CLASS, NODE, or PROPERTY specific linkback targets. The administrator must ensure that all of these targets are hidden or un-hidden according to the configuration.


next up previous contents
Next: LINKBACK syntax Up: Using linkbacks Previous: Linkbacks with sub-classes   Contents
root 2017-02-23