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

Canonical
3 February 2026

AWS IoT Greengrass comes to Ubuntu Core

Ubuntu Article

AWS’s open source edge run time meets Canonical’s fully containerized OS for devices delivering a supported and robust end-to-end answer for enterprises looking to develop their own IoT hardware and solutions. London, February 3, 2026 — Canonical and AWS are pleased to announce the release of the new snap for AWS IoT Greengrass, making th ...

Canonical
3 February 2026

Tutorial: getting started with AWS IoT Greengrass on Ubuntu Core

Ubuntu Article

We recently announced that you can now benefit from the combined power of Ubuntu Core and AWS IoT Greengrass to bring the computation, storage, and AI capabilities of the cloud closer to the edge. AWS IoT Greengrass is an open source edge runtime and cloud service that extends Amazon Web Services (AWS) capabilities to physical ...

Lidia Luna Puerta
23 January 2026

How to avoid package End of Life through backporting 

Ubuntu Article

When a Git vulnerability hit systems past Ubuntu package end of life, teams had to reassess security options. Learn how to stay protected beyond standard support. ...