RHEL6 – RTFM Apache Web Server

King-James-BibleThere is a lot to know and remember about configuring Apache as you may or may not have seen from the numerous posts I have written on the subject, and the reality is that no one is going to be able to memorize each and every settings, configuration, and directive. Sure you can bing it or google it , you can even alta-vista it, but only if you have internet access at the time, however there is always a chance that you might get some bad information. So why not refer to the official httpd documentation. You know RTFM and what not.

By and large the best bet for HTTP documentation is the http-manual package that can be installed via yum. It installs to /var/www/manual

# yum -y install httpd-manual

Now one bit of information to note. The documentation installed via the httpd-manual package are in html format, so it not advised that you try to view it with an editor like vim or emacs.  You are going to need an text based web browser like lynx or elinks. I prefer lynx in this situtation, so lets install it.

# yum -y install lynx

Now you can peruse the documentation  as you see fit using lynx.

# lynx /var/www/manual/howto/auth.html

Below are some of the better and more often useful docs that I think that could be found useful in a crunch. Note our base directory is /var/www/manual

  • vhosts/named-based.html – which outlines configuring named-based virtual hosts
  • ssl/ssl_howto.html – which outlines has a nice section on HTTP Basic Authentication.
  • howto/cgi.html – which nicely documents creating a custom cgi directory
  • howt0/auth.html – more on HTTP Auth using htpasswd

Yup thats a lot of very good documentation right there, and its actually written by the people who wrote apache, not some 13 year old kid taking his first shot running apache on Ubuntu.

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How to Disable DRS for one VM in a DRS Enabled Cluster

Vmotion_archVMware DRS (Distributed Resource Scheduler) is a feature of ESX that balances
computing workloads with available resources in a virtualized
environment. 

When you enable a cluster for DRS, VirtualCenter continuously monitors the distribution
of CPU and memory resources for all hosts and virtual machines in the
cluster. DRS compares these metrics to what resource utilization
ideally should be given the attributes of the resource pools and
virtual machines in the cluster, and the current load. Note that DRS is only available in ESX Enterprise or above.

When DRS is enabled in a cluster, ESX then will automagically vmotion guest VMs to other hosts in your cluster in an attempt to ballance out the load evenly across the cluster. However, sometimes this behavior is not always desired. For exmaple if you have a large VM that you want to stay pinned to a particular host.

In order to override the default DRS cluster settings for a vm, you need to do the following.

  1. Right Click on your cluster and then click on "edit settings"
  2. Under DRS, click on "Virtual Machine Options"
  3. Locate the particular VM and the drop down box under "Automation Level"
  4. Change "Default (Fully Automated)" to "Manual"