/etc/mcp/override best practices

[Dan Pritts]

Hi folks -

>From what I've been able to piece together, I should modify files in /etc/mcp/override if i want to customize system files on the isilon nodes.   I have never seen this specifically explained, but it comes up in context in the list archives and in EMC support documents.

In my case I want to do things like modify sshd ports, add some allow & deny lines to httpd.conf, add a few shell aliases & change the shell prompt, etc. 

i've seen some mention that if i change it on one node it will automatically copy to other nodes.  In other cases, i see folks using isi_for_array to do it instead.  I've also seen mention that if you modify configuration files daemons will automatically restart. 

I presume I have to put complete configuration files in /etc/mcp/override, there will be no merging or including of files.

So...any best practices?

thanks!

--
Dan Pritts
ICPSR Computing & Network Services
University of Michigan
+1 (734)615-7362

[Cory Snavely]

We've made such mods on a single node, and the cluster distributes them.
Depending on the mod, some variation of isi_for_array may be needed to
restart services to effect the changes (eg sshd).

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[Chris Pepper]

Dan,

We run a bunch of cluster batch jobs. We were originally told to put them in /etc/mcp/templates/crontab, but that has been deprecated in favor of /etc/mcp/override/crontab.smbtime. Changes made there are automatically and immediately replicated to the real crontab on all nodes crontab.smbtime is combined with other files to build the real (complete) crontab file.

Note that cluster cron jobs require you to specify the user to run the job, and that they run on *all* nodes. Ours all have a simple 'if' statement to drop out on all nodes except one.

Chris

[Eric Peskin]

Dan,

Some files do have special handling and merging. Take a look at the
files in the directory /etc/mcp/templates/
For example,
/etc/mcp/templates/apache2.conf
begins with the comments:

# X: ----------------
# X: This file is used to automatically generate the httpd configuration
# X: file based on configuration information obtained from the Isilon
# X: Web UI.
# X: The resulting configuration file is stored at
# X: /usr/local/apache2/conf/httpd.conf
# X: ----------------

So I'd put modifications for the web server into the template file
/etc/mcp/templates/apache2.conf
You can then restart the web server from the UI, at which point it
will splice in any parameters it gets from the UI (for example,
filling in the DocumentRoot) and sends the merged httpd.conf to all
the nodes.

The catch is that if/when you upgrade, you can lose the changes. So
keep track of what you have changed.

Eric