Optimization, troubleshooting and monitoring of virtual infrastructures is like a scientific subject in itself and one of my IT-passions. Together with my buddy Dr. Jens Söldner I have published two articles in german IT-Administrator magazine (German Language), which cover the subjects above.
ESXi system disks do not require a lot of storage space on their boot media. That’s the reason why many installations use small and less expensive flash media instead of disks (and SCSI controller). It can be USB flash media for example or a SD-card.
The quality and reliability of these media varies. Even from batch to batch of the same type and the same vendor. Heavy write activity, but also heavy reading may significantly shorten the lifespan of flash media. In recent times we had to witness media that failed after less than a year in service. As long as the host keeps running this isn’t a bigger problem, because all crucial components are kept in ESXi host RAM. With VMtools-Image the situation is different. Each time a VM requests access to the image it will be read from flash. Especially VDI environments have a high read rate onto VMtools-Image, which may ‘burn’ the media.
VMware is aware of the problem and has introduced a migitation of the issue starting with ESXi 6.0 U3. It is not active by default and has to be activated manually. The migitation is fairly simple. During host boot VMtools-Image will be mapped into RAMDisk. Read access will be served from RAM and the lifetime of the media will be extended.
I will show here how to activate the option with web-client, PowerCLI or ESXi shell.
Host upgrades with custom images offer extended driver support for vendor specific hardware or agents. You’ll get drivers that are not included in a standard VMware (Vanilla) image. Upgrading with customized images may lead into trouble while updating existing driver packages. There used to be a nasty bug with the lsiprovider package on Fujitsu ESXi 5.1 images. Another example was the “death by upgrade” bug (blog post in German) when upgrading a customized Fujitsu installation to ESXi 6.0. There are other examples from different vendors in the hall of shame.
VMware VIC (vSphere Integrated Containers) is an elegant way to run container workloads alongside with regular VMs in your datacenter. You’ll get best of both worlds. Developers can use container tools as usual but with added high availability and flexibility of a vSphere cluster.
I’m going to give a little primer on VMware Integrated Containers (VIC) and how to use them.
Create distributed portgroups on a vDS that we will use for containers. We need a public dPG and a bridge dPG.
Create a VIC user to interact with vCenter. For example a standard domain user who gets permissions on vCenter to deploy and delete VMs. This user will be granted permissions to vCenter later during setup.