IP addresses are important resources and must be carefully managed to avoid duplicated IP issues, which are sometimes very hard to troubleshoot. I still remember that it took a few of us couple of days to root cause a failing new feature, which worked sometimes and did not other times. Because it’s a new feature, we mostly thought it was somehow our bug in code. It turned out not, but caused by the vCenter we were testing actually used a duplicated IP address.
With the erratic pattern, it’s simply not easy to develop a good hypothesis for troubleshooting in the right direction. A good lesson learned from there is that when you have no clue, try duplicated IP. To avoid the issue, we sometimes use DHCP to dynamically allocate the IP address. If all DHCP allocated, this is less likely to happen. But most environments have both approaches, or simply no DHCP at all. So the duplicated IP is always a potential issue.
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Enough said about the importance of the IP address management.
To track the IP allocation, most companies I know of use wiki page or a spreadsheet to track the IP and user. There is nothing wrong with this approach at all. The only issue is that it takes time to do it, and more importantly good discipline to do it consistently. The latter is actually hard to stick with especially there are a group of people working together. If you have partially tracked IP addresses, the problem does not go away, or could go even worse because we all assumed IPs are tracked.
Is there a way that tracks the IP allocation automatically?
Thanks to VMware Tools, you can actually do that fair easily. No matter how you get the IP for your VM (static, DHCP), the VMware Tools reports it to the vCenter server. The IP address would then be displayed on the vSphere Clients.
Of course, you don’t want to check each VM’s IP address before you determine a free IP address on a subnet. That’s simply too much and too tedious work. The IP allocation has to be in one place, and organized, sorted, and displayed the same way as in a spreadsheet or wiki page. With table like format, you can quickly scan the IP address be used, and identify these not used.
That’s exactly what DoubeCloud vSearch product brings to you. With one click, you can list all the IP addresses in all your vCenter servers. It’s grouped by vCenter server, and by the subnet. For each IP address, it reports whether it’s DHCP or static IP, which VM or ESXi server uses it. Even better – the VM or ESXi names come with hyperlinks, which, upon clicking, lead to the detailed page showing more information and actions for more management operations. You can also filter any field like IP address, origin, owner type, etc using the filter fields on top of the table.
With this tool, you no longer have to do the tedious work of keeping recording of IP address either wiki page or spread sheet. That means you can focus on fun projects and skills that advance your careers. Visit here for a free 35 day trial.