It’s easy to read because you already know ansible. But given a large sample size of linux or unix admins, I would say there would be very few who wouldn’t fully understand the shell script and it wouldn’t take more than 2 minutes to open the man page of certain commands they don’t understand and figure it out.
Here's an example (click to expand)
if [ -d /mnt/orabkp ]
then
ls -l /mnt/orabkp > /dev/null
ok=$(mount -l | grep -c bkp)
if [ ! $ok -le 0 ]
then
for foo in $(ls -l /opt/orabkp/ | grep drwx | awk '{print $9}')
do
if [ "$foo" != "fakedb" ]
then
if [ ! -d /mnt/orabkp/$foo ]
then
mkdir /mnt/orabkp/$foo
touch /mnt/orabkp/$foo/.mark
mkdir /mnt/orabkp/$foo/autobackup
mkdir /mnt/orabkp/$foo/backupset
chown -R oracle:dba /mnt/orabkp/$foo
chmod 775 -R /mnt/orabkp/$foo
chmod 777 /mnt/orabkp/$foo/.mark
fi
fi
fi
fi
This is when I was just starting to write shell scripts, now I could write them better, but I didn’t modify my original one, just to make a point.
The background: oracle backups were made by having backup scripts for each DB, in folders in /opt/orabkp, each folder being named after the DB instance name. All the script does is verify if the folder /mnt/orabkp exists, if it does, it runs ls, just to make sure the NFS is mounted. If the mount command detects and nfs mount in that location, it continues. It checks if the folders already exist on the NFS server and if it doesn’t, it means it’s a new db that needs to be backed-up, so it creates its folder and the file .mark. The last file is used to verify that the NFS is mounted before doing the db dump.
I have used this script hundreds of times when new dbs were created, along with another one (they were twin scripts, now that I think about it, I could have just combined them in one). I have more scripts like those that I used to automate tasks. Could I have used ansible for this? Sure, if I learned it, but the script above is simple, any linux sysadmin worth their salt will understand it (I don’t work at that company anymore, so someone will look or has looked already at it to understand what it does) and I wrote it in probably less than 10 minutes. I don’t know how long it would have taken me to replicate the same tasks in ansible. If I knew ansible, probably around the same time, but since I didn’t, probably a lot more, time that I didn’t have.
And to run it on multiple machines, I would use pssh
pscp.pssh -h HOSTS_FILE -p 20 -o /var/log/pssh-output-logs/ -e /var/log/pssh-error-logs/ the-above-script.sh /root/scripts/
pssh -h HOSTS_FILE -p 20 -o /var/log/pssh-output-logs/ -e /var/log/pssh-error-logs/ "/root/scripts/the-above-script.sh"
Just like in ansible, I had different hosts files with the servers I wanted to deploy and run the scripts on, in this case, oracle servers. The basics of this is that pscp does a “scp file user@host:/path/” for each host in the hosts file you give it, with -p being the number of parallel threads. Then pssh would run the script on all of them and I would be done with my “work” and more to my next task.
There weren’t a lot of tasks that I could automate, I had a few, among them being changing repos, updating, installing all the software on a new VM, or adding ssh keys to a lot of VMs authorized_keys users when someone new came along, removing a ssh key from all the users’ authorized_keys on the VM, or create or delete a user on all VMs when someone new came along. I’m certain, all doable in ansible.
Now I’m not a sysadmin anymore, so I’m not sure how worth it would be learning ansible. If the opportunity comes along, I may, but if I need to do things for myself that would be done easier by automation, I will probably go back to writing shell scripts.
