pssh4cssh

Use your existing ClusterSSH cluster groups with parallel-ssh tools. No duplicate host lists -- one source of truth in ~/.clusterssh/clusters, including nested group expansion.

Requirements

sudo apt install pssh clusterssh

Install

git clone https://github.com/oneidprod/pssh4cssh.git /path/to/pssh4cssh

Add to your ~/.bashrc (use the path where you cloned it):

source /path/to/pssh4cssh/pssh4cssh.sh

Then reload (or open a new terminal):

source ~/.bashrc

Usage

All commands take a cluster group name as the first argument, followed by the normal arguments for that tool.

parallel-ssh -- run a command on all hosts in a group

pssh-c vps-all "uptime"
pssh-c vps-arm "df -h /"
pssh-c vps-amd "free -h"

parallel-scp -- copy a file TO all hosts

pscp-c vps-all /local/file.conf /remote/path/

parallel-rsync -- rsync to all hosts

prsync-c vps-all -r /local/dir/ /remote/dir/

parallel-slurp -- pull a file FROM all hosts

pslurp-c vps-all /var/log/syslog ./logs/

Nested groups

Groups that reference other groups in your clusters file are expanded recursively. For example if your clusters file contains:

vps-amd ubuntu@host1 ubuntu@host2
vps-arm ubuntu@host3 ubuntu@host4
vps-all vps-amd vps-arm

Then pssh-c vps-all will expand to all four hosts automatically.

Included scripts

df-summary

Shows disk usage for /dev/sda1 and NFS mounts across a cluster, sorted by free space.

# All servers
./df-summary

# Specific group
./df-summary vps-arm

Output is split into two sections:

=== /dev/sda1 ===
HOST                           FILESYSTEM   SIZE     USED     FREE     USE%
----------------------------------------------------------------------------------------------
ubuntu@10.0.0.1                /dev/sda1    45G      28G      18G      61%
ubuntu@10.0.0.2                /dev/sda1    45G      42G      3.4G     93%

=== NFS Mounts ===
HOST                           FILESYSTEM   SIZE     USED     FREE     USE%
----------------------------------------------------------------------------------------------
ubuntu@10.0.0.3                10.0.0.1:/var/nfs/shared 45G   35G      11G      77%

Real-world example

logrotate-wallets uses pssh4cssh to deploy a logrotate config to a fleet of VPS servers in one shot:

pscp-c vps-all wallet-debug-logrotate.conf /home/ubuntu/
pssh-c vps-all "sudo mv ~/wallet-debug-logrotate.conf /etc/logrotate.d/wallet-debug && sudo chown root:root /etc/logrotate.d/wallet-debug && sudo chmod 644 /etc/logrotate.d/wallet-debug"

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Clusters file format

Each line is a group name followed by its members separated by spaces. Members can be hostnames, user@host addresses, or other group names for nesting:

# Simple group
vps-amd ubuntu@10.0.0.1 ubuntu@10.0.0.2 ubuntu@10.0.0.3

# Another group
vps-arm ubuntu@10.0.1.1 ubuntu@10.0.1.2 ubuntu@10.0.1.3

# Nested group -- expands vps-amd and vps-arm automatically
vps-all vps-amd vps-arm

Lines starting with # are comments and are ignored. You don't need ClusterSSH installed -- just create ~/.clusterssh/clusters with your groups.

Custom clusters file

By default pssh4cssh reads ~/.clusterssh/clusters. Override with:

export CSSH_CLUSTERS=/path/to/your/clusters

License

MIT © oneidprod