It’s not always enough to have only one virtual machine for testing purposes. More – it’s not enough in most of the cases. One of such cases is – for example – when you want to try a multi-node configuration for software like Hadoop or Cassandra, or make a failover test of your system. For me most comfortable and useful is to have a configuration that allows guest system to use the Internet (usually it’s a default, NAT mode) but also makes it possible to easily connect to guest system from host system (not by port forwarding) and makes guest systems able to “talk” with each other – it’s good enough to mimic most of production configurations I use. To do this we need to setup a two-network-cards configuration for alle the guest systems we have. This article is about how to make it work.
I was playing a bit with some virtual machines I need for testing, when after a reboot I noticed that sendmail is starting very slow – it took about 3-4 minutes to have it working. I’ve checked the log too see what’s wrong:
[root@hdps01 ~]# tail /var/log/maillog Jul 11 21:26:43 hdps01 sm-msp-queue: My unqualified host name (hdps01) unknown; sleeping for retry Jul 11 21:27:43 hdps01 sm-msp-queue: unable to qualify my own domain name (hdps01) -- using short name Jul 11 21:27:43 hdps01 sm-msp-queue: starting daemon (8.14.4): queueing@01:00:00
So, what was the problem?
Yesterday there was a Python Riddle competition on EuroPython. I did quite well, but I didn’t know how well until I saw the results. Then I realized how stupid thing I did to NOT win MacBook. Here’s the short story.