Resolve .local Through Nameserver With Netplan

When using netplan it is easy to force .local DNS requests to go to you nameservers instead of being only resolved locally (the default and standard).

This also works with all other strange .WHATEVER domains you may have lying around in your organization.

Snippet from netplan configuration:

 nameservers:
        addresses:
          - X
          - Y
        search:
          - local
          - myotherstupiddomain

DNS Resolution Everywhere

Usually at leas one of those is present on any system dig nslookup host But sometimes the usual suspects don’t work, especially in container-land. After trying them you may try some more involved/unknown things: getent Part of glibc, this will probably work on nearly every system. getent hosts example.org Or, if you specifically want to query A or AAAA records. getent ahostsv4 example.org getent ahostsv6 example.org Using Python2 Or Python3 Given this depends on glibc it is more of a alternative than another real solution [Read More]

curl: Modify DNS Resolution

You can intercept normal name resolution in curl with the --resolve parameter allowing you to do things like talk to a specific site of a DNS load-balanced setup or talk to a new deployment not yet made productive. You can specify the resolve option multiple times so you can even catch redirects and move them to where you want as well. It’s important to note that this intercept does only work on the ports you specify in the entries. [Read More]

How SELinux screws with scripts when run over VMware Tools

SELinux by default prohibits certain things from working through VMware tools (Ansible connection or plain API).

This can be solved two ways:

  • Disabling SELinux: BAD, but easy
  • Writing a custom SELinux policy: complicated but more secure

Note: Adding/Changing this policy through a VMware tools connection is thankfully possible

Example policy

This policy is the base for a VMware tools policy and allows entering the rpm context (yum).

module custom-vmtools 1.0;

require {
        type rpm_script_t;
        type vmtools_unconfined_t;
        class process transition;
}

#============= vmtools_unconfined_t ==============

allow vmtools_unconfined_t rpm_script_t:process transition

Delete Your Old VMware Snapshots

For the love of Pete, please delete your old snapshots regularly! Old snapshots have caused incidents and even outages more than once in my career and it is really easy to preemptively look for them and get them removed before anything happens. Why To put it plainly, they can cause issues - like 03:00 in the morning pager alert issues and additionally eat up storage space like crazy. Degraded performance of the VM having the snapshot Degraded performance to full outages for other VMs on the same data store due to rapidly increasing snapshot sizes VMware recommends a series of steps to reduce risk when using snapshots: [Read More]