Skip to main content
  1. Blog
  2. Article

Canonical
on 17 June 2014

OpenStack One-Liners

One-line bash commands for managing, deploying and testing OpenStack and related components, hypervisors and containers.  Some simple and obvious, some cool and questionable, hopefully all useful.  Check back on this post, I’ll likely add more. #1 – Watch Nova Compute for Non-Active Instances on Openstack Outputs total instance count and non-active instances. Useful for keeping an eye on potential problem VMs in a PAUSED, ERROR, SHUTOFF or other non-active state. Command: watch --interval=1 'nova list --all-tenants | wc -l && nova list --all-tenants | grep -v "ACTIVE"' #2 – Ping a List of Hosts Forever:  1-Line Loop A simple one-line while loop containing a for loop to ping a list of hosts each with one packet, followed by a 1/4 second iteration delay and an output text filter. Command: while true; do for h in bcu vxu rbu; do ping ${h} -c 1 | grep ttl; sleep 0.25; done; done;   #3 – Watch Cinder Volumes and Snapshots and Glance Images in Openstack Useful for working with volumes, snapshots and images in small Openstack deployments. watch --interval=1 "cinder list && cinder snapshot-list && glance image-list"   #4 – Watch Linux Containers and Directory-Backed Storage I find this one handy when I need to monitor LXC containers on Ubuntu Server – Precise Pangolin, Trusty Tahr, Utopic Unicorn and later.  The Ubuntu Server Guide has a detailed section on LXC usage. watch "sudo lxc-ls --fancy --nesting && sudo ls -Ralh /var/lib/lxc/"   #5 – Watch Your Disk Space Disappear This is a tail-style output of the free space on /. while true; do df -h / | grep '/' | awk '{ print $4 }'; sleep 1; done 6.1G 6.1G 6.0G 6.0G 5.9G 5.8G 5.7G 5.7G  

Related posts

Jonathan Beri
18 June 2026

So you need to add microcontrollers to your fleet: now what?

Ubuntu Article

Your Ubuntu Core fleet is running beautifully. OTA updates roll out in minutes. Every device is strictly confined, cryptographically attested, and carrying a 10 to 15 year long term support (LTS) commitment. The operational team sleeps soundly. Then the product roadmap meeting happens. The industrial floor needs vibration sensors on every ...

Ishani Ghoshal
17 June 2026

Validating real-world skills through Canonical Academy

Ubuntu Community

In an increasingly volatile job market, standing out from the competition is vital. For many in the open source community, formal recognition for self-taught skills is a significant challenge. These skills are often built through hands-on hobbies, side projects, and deep community contributions. While the market is flooded with certificat ...

Bertrand Boisseau
17 June 2026

Virtualized Android comes to Anbox Cloud

Ubuntu Article

With our latest 1.30.0 Anbox Cloud release, available today, we are introducing one of the most significant evolutions of the platform to date: support for virtualized Android.  For the first time, Anbox Cloud can launch complete Android system images inside lightweight virtual machines, managed and orchestrated through the same Anbox API ...