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

Miguel Divo
19 January 2026

Showcasing open design in action: Loughborough University design students explore open source projects

Design Article

Last year, we collaborated with two design student teams from Loughborough University in the UK. These students were challenged to work on open source project briefs. Team 1 focused on non-code contributions, while Team 2’s brief was to create a unified documentation experience, giving them a chance to apply their design skills to real-wo ...

Canonical
15 January 2026

Canonical Ubuntu and Ubuntu Pro now available on AWS European Sovereign Cloud

Ubuntu Article

Canonical announced it is a launch partner for the AWS European Sovereign Cloud, with Ubuntu and Ubuntu Pro now available. This new independent cloud for Europe enables organizations to run secure, enterprise workloads with full operational autonomy and EU data residency. By combining the performance and expanded security coverage of Ubun ...

Lidia Luna Puerta
14 January 2026

How to build DORA-ready infrastructure with verifiable provenance and reliable support

Ubuntu Article

DORA requires organizations to know what they run, where it came from, and how it’s maintained. Learn how to build infrastructure with verifiable provenance. ...