--- title: OpenStack One-Liners description: '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 […]' url: https://canonical.com/blog/openstack-one-liners?format=md --- 1. [Blog](https://canonical.com/blog) 2. Article --- [Canonical](https://canonical.com/blog/author/canonical "More about Canonical") 17 June 2014 # OpenStack One-Liners --- Share the article 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 [Get in touch Interested in running Ubuntu in your organization?](https://ubuntu.com/about/contact-us/form) ## Sign up for our newsletter Get the latest Canonical news and updates in your inbox. Work email: \*I agree to receive information about Canonical's products and services. By submitting this form, I confirm that I have read and agree to [Canonical's Privacy Policy](https://canonical.com/legal/dataprivacy). Sign up ## Share on --- ## Related posts [### Canonical joins the Open Secure AI Alliance](https://canonical.com/blog/open-secure-ai-alliance) Canonical is now part of the Open Secure AI Alliance, announced by NVIDIA with partners across cloud computing, cybersecurity, enterprise software, open source foundations, and... [Canonical](https://canonical.com/blog/author/canonical) 28 August 2026 [### Arduino® VENTUNO™ Q is available for pre-order with Ubuntu pre-installed](https://canonical.com/blog/arduino-ventuno-q-is-available-for-pre-order-with-ubuntu-pre-installed) London, UK – August 25, 2026 – Following our initial collaboration announcement in March 2026, Canonical and Arduino (a subsidiary of Qualcomm Technologies, Inc.) are excited... [Canonical](https://canonical.com/blog/author/canonical) 25 August 2026 [### Advantech AOM-2721 is now Ubuntu Certified](https://canonical.com/blog/advantech-aom-2721-ubuntu-certified) Canonical announces that the Advantech AOM-2721 is officially joining the list of Ubuntu Certified Hardware. [Mikhail Khazov](https://canonical.com/blog/author/khazov-m) 13 August 2026 [### Canonical integrates NVIDIA Nemotron 3.5 Lightning with Ubuntu for always-on AI agents](https://canonical.com/blog/nvidia-nemotron-3-5-lightning) Canonical is pleased to announce that NVIDIA’s newly introduced NVIDIA Nemotron 3.5 Lightning, an open, customizable model built for always-on AI agents, is now available on... [Canonical](https://canonical.com/blog/author/canonical) 11 August 2026