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Showing posts from October, 2015

Ansible's for loops

Recently, me and a team hit a big limitation with Ansible that really took me by surprise.  For loops, can only iterate over a single task and not roles or playbooks.  This post will discuss why it was a surprise, what we did to get around it and (briefly) what Ansible 2 introduces.

Pre Ansible 2
The original issue really took me by surprise since the documentation on for loops showed a huge number of possibilities (including conditionals, looping over arrays etc etc) that suggested to me it was Turing-Complete and easily capable of meeting all our looping needs.  So when I needed to assign a role multiple times (dynamically from a list) I was shocked to find that it couldn't be done.

I'm not the only one who was caught out by this.  See here, here and here.

Why this wasn't supported really puzzled me.  Some on my team concluded that it must be due to the way Ansible works internally and would perhaps require a lot of re-writing to support the feature.  However, Michael D…