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

Luci Stanescu
8 May 2026

Dirty Frag Linux kernel local privilege escalation vulnerability mitigations

Ubuntu Article

Two local privilege escalation (LPE) vulnerabilities affecting the Linux kernel have been publicly disclosed on May 7, 2026. One of the vulnerabilities has been assigned the ID: CVE-2026-43284. The other CVE ID is pending. Both are referred to as “Dirty Frag.” The affected components are Linux kernel modules. The first vulnerability impac ...

ilvipero
6 May 2026

Three weeks to go: A sneak peek of the Ubuntu Summit 26.04 experience

Ubuntu Article

The countdown to the Ubuntu Summit is officially on! We are just three weeks away from Ubuntu Summit 26.04, and the orange energy levels in our community channels are peaking. We’ve been reviewing the talk submissions, and have been blown away by the passion and creativity of our circle of friends. Once again, the schedule ...

Rajan Patel
4 May 2026

How to use Ubuntu on Windows

Ubuntu Article

Why run Ubuntu on Windows? It’s about getting the best of both worlds. ...