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
12 March 2026

AppArmor vulnerability fixes available

Ubuntu Article

Qualys discovered several vulnerabilities in the AppArmor code of the Linux kernel. These are being referred to as CrackArmor, while CVE IDs have not been assigned yet. All of the vulnerabilities require unprivileged local user access. The impact of these vulnerabilities ranges from denial of service to kernel memory information leak, rem ...

David Beamonte
11 March 2026

The bare metal problem in AI Factories

MAAS MAAS

As AI platforms grow into large-scale “AI Factories,” the real bottleneck shifts from model design to operational complexity. With expensive GPU accelerators, hardware failures and inconsistent configurations lead directly to lost throughput and reduced return on investment. While Kubernetes orchestrates workloads, it cannot fix broken ph ...

Canonical
10 March 2026

Fast-tracking industrial and AI deployment on Renesas RZ platforms 

Canonical announcements Article

Certified Ubuntu 24.04 LTS images now available Canonical is pleased to announce the general availability (GA) of certified Ubuntu 24.04 LTS and Ubuntu Core 24 images for the Renesas RZ/G2L and RZ/G2LC 64-bit microprocessors (MPUs) platforms. With a production-ready Ubuntu version, users can benefit from enterprise-grade security, long-te ...