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

Benjamin Ryzman
11 February 2026

What is RDMA?

AI Networking

Modern data centres are hitting a wall that faster CPUs alone cannot fix. As workloads scale out and latency budgets shrink, the impact of moving data between servers is starting to become the most significant factor in overall performance. Remote Direct Memory Access, or RDMA, is one of the technologies reshaping how that data moves, ...

Isobel Kate Maxwell
10 February 2026

Building new revenue streams: 3 strategic cloud opportunities for telcos in 2026

Cloud and server Telecommunications

PWC claimed the ‘fundamental challenge’ behind slowing growth is that telecom’s ‘core products and services’ are ‘becoming commodities.’ The way forward lies in modernizing and diversifying: evolving from traditional telecommunications to ‘techco’ (technology company) services. In 2026, many of these opportunities will come from cloud com ...

Jehudi
6 February 2026

SQL Server 2025 is generally available on Ubuntu 24.04 LTS

Data Platform Article

Microsoft has announced the General Availability of SQL Server 2025 on Ubuntu 24.04 LTS. Learn about the new CU1 features, including OS-level observability, Contained Availability Groups, and native vector support for enterprise workloads. ...