Category: Linux Luvin’

Run multiple ssh commands in parallel with GNU Parallel

Every true sysadmin has been in this predicament — “I need to run this command on a bunch of machines.” The typical approach is to create a for loop, and run the command serially. This works well, but if a)

Elasticsearch cluster administration notes

If a replica shard is in an INITIALIZATION state and the primary shard is healthy, then the shard is being replicated from the primary to the replica. You can use the cat API to get this state:

Now, we

Installing OpenVZ templates in Proxmox

Promox has built-in support for installing templates, but they’re pretty outdated and not well-maintained.  openvz.org, on the other hand, regularly updates their templates, and has a wide selection to choose from. In order to make these templates available for use

IMAP Append – Message contains bare newlines

The Cyrus IMAP server (which is used by FastMail, FYI), is pretty picky when it comes to enforcing RFCs.  When performing a recent email migration (from Zoho, which is less picky), I got a boatload of errors along the way.

Create multiple Proxmox containers via script

There are times when I need to create a number of OpenVZ containers in Proxmox at once, which would take way too long via the user interface.  There are a number of ways to accomplish this programmatically, but the most

rsync to multiple hosts in parallel

 

 

Migrating from one Chef server to another

It happens — you’re on a server that just can’t be upgraded any further, and you need more resources.  Or, you need to backup a Chef server.  Or, you need to setup a QA instance.  Or, you need to finally

Change Chef Server settings after installation

Just about every significant aspect of Chef Server is configurable, although the defaults are okay for most.  The configuration options are documented at http://docs.opscode.com/config_rb_chef_server_optional_settings.html . Note, though, that the chef-server.rb described in the article was nowhere to be found on my server.

Use nginx as a reverse proxy to speed up your WordPress site

Everyone loves speed.  That includes your site’s visitors.  If you run a WordPress site, WP Super Cache is a pretty cool plugin that generates static files from your dynamic content, and serves those to your users instead of dynamically generating the same

Update your Ubuntu/Debian servers with Chef

If you need a hands-off way to update your Ubuntu or Debian servers, Chef’s Knife utility provides an easy way to do this (and parallelize it!). The following will update your packages in an unattended way.  In other words, all

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