Technology articles

A common need for deployments in production, is to have the possibility of taking backups of your working virtual machines, and export them to some external storage. Although libvirt offers the possibility of taking snapshots and restore them, those snapshots are intended to be managed locally, and are lost when you destroy your virtual machines. There may be the need to just trash all your environment, and re-create the virtual machines from an external backup, so this article offers a procedure to achieve it. First step, create an external snapshot So the first step will be taking an snapshot from your running vm. The best way to take an isolated backup is using blockcopy virsh command. So, how to proceed? 1. First you need to extract all the disks that your vm has. This can be achieved with domblklist command:   DISK_NAME=$(virsh domblklist {{domain}} --details | grep 'disk' | awk '{print $3}') This will extract the name of the device that the vm is using

Setup an NFS client provisioner in Kubernetes One of the most common needs when deploying Kubernetes is the ability to use shared storage. While there are several options available, one of the most commons and easier to setup is to use an NFS server. This post will explain how to setup a dynamic NFS client provisioner on Kubernetes, relying on an existing NFS server on your systems. Step 1. Setup an NFS server (sample for CentOS) First thing you will need, of course, is to have an NFS server. This can be easily achieved with some easy steps: Install nfs package: yum install -y nfs-utils Enable and start nfs service and rpcbind: systemctl enable rpcbind systemctl enable nfs-server systemctl start rpcbind systemctl start nfs-server Create the directory that will be shared by NFS, and change the permissions: mkdir /var/nfsshare chmod -R 755 /var/nfsshare chown nfsnobody:nfsnobody /var/nfsshare  Share the NFS directory over the network, creating the /etc/exports file: vi /

TripleO Queens has an interesting feature that is called 'composable networks'. It allows to deploy Openstack with the choice of networks that you want, depending on your environment. Please see: https://docs.openstack.org/tripleo-docs/latest/install/advanced_deployment/custom_networks.html By default, the following networks are defined: Storage Storage Management Internal Api Tenant Management External The external network allows to reach the endpoints externally, and also to define networks to reach the vms externally as well. But to have that, it is needed to have a network with external access, routable, on your lab. Not all labs have it, specially for CI environments, so it may be useful to deploy without it, and just have internal access to endpoints and vms. In this blogpost i'm just going to explain how to achieve it. First make a copy of your original tripleo-heat-templates, to another directory /home/stack/working-templates, and edit the following fil