terraform-provider-nutanix: Patch to allow some changes to be hotplug

Second patch for the nutanix provider for terraform.
This time it has been merged into master, so is publicly available.

As I wrote in the commit description:

Hot-plug Options (always):

  • Name
  • Description

Hot-plug Options just when increasing it:

  • num_vcpus_per_socket
  • num_sockets
  • memory_size_mib

Which are the changes that nutanix can perform online (when the VM is running).

terraform-provider-nutanix Patch to ignore CDROM’s

I’m hitting the same problem as described on issue #69.
Depending on terraform version, the 2nd apply after the 1st one (creating vm’s) will cause:

  • Reboot VM and remove that cdrom (terraform v0.10).
  • Ask to remove the cdrom and if removed, the vm crash (kernel panic/bsod) as you’re hot-removing a IDE bus drive (terraform v > 0.11) and IDE is not hot plug (usually).

I’ve “patched” the provider so it ignores CDROM && IDE (bus) changes.
Maybe is not the best solution but as we’re not using cdrom drives at all, using this little patch is a good option for us.

So feel free to clone, test, fork…
https://github.com/Jorge-Holgado/terraform-provider-nutanix

PS: I’ve move the path to a standalone branch, so you can apply just only this patch.

Ceph Troubleshooting: Debugging CRUSH maps

The last days I’ve been busy trying to find a “error” on my CRUSH map.
I found that some of my OSD’s where underused or unused at all… I didn’t know why, cause I built a CRUSH map from scratch with the common architecture based on datacenter, rack & cluster. And It was correct from the ceph point of view (It was running on the cluster).

I decided to simplify the map to a much simpler one.
Something like this:
Simple CRUSH map

Continue reading “Ceph Troubleshooting: Debugging CRUSH maps”

Ceph Troubleshooting: Adding new monitors to cluster

In my ceph-to-production sprint I found that 4 monitors are not enough… It is a pair number and everybody knows what happens when there’s a pair number on a cluster and some of the quorum member fails :-)
So I decided to add 2 more for a total of 6. We have 2 CPD’s, If one of the CPD’s goes down, there will be 3 monitors online to elect the new master (I hope that works and not as the official documentation says)

That was the easy part…

Continue reading “Ceph Troubleshooting: Adding new monitors to cluster”

Cloud-init: The great forgotten

A little time ago (more than 1 year ago) I began investigating cloud-init. I saw some redhat paper talking about cloud-init and it seemed to be really powerful simplifying massive vm deployments.
Someone close to me told me that: “don’t lose your time, we’ll use terraform/docker/k8s/whatever

But the inception was already done, I read the documentation and started testing the technology.

What I’ve seen is that cloud-init is everywhere: I think that all linux “cloud” vm’s are using it. It’s really sturdily and simple, it does what it is supposed to do… That is part of its greatness and of its weakness.

The good part is well known: cloud-init service starts when the vm starts and does what you tell it to do through a YAML script: Installs software, create users, perform basic configs…
Its weakness is that cloud-init is a very simple software designed for the cloud, if your cloud architecture is not standard, you will have to make some tricks to bypass them.

For example, I was not using dhcp for VM’s networking and booting a VM with cloud-init without dhcp is really tricky… You can see a YAML script for static network here:

All that has given me a background and a global vision to understand the inner technology used on “cloud” platform (any cloud platform)… it seems that time has proved me right :-)

Ceph (I): Basic Architecture

Recently I did a basic architecture document (and training) of ceph.

This document will give you the basics to understand the role of the Ceph architecture pieces like can be:

    • Monitor Nodes
    • Disk (aka OSD) nodes
    • Metadata Nodes
    • Gateway Nodes

And what the words “RADOS” and “CRUSH” means (again is a very basic definition)

Enjoy with the document/presentation!