Let me try to better illustrate my question with a more concrete example. Imagine an app Foo that has two tiers: Apache and MySQL. Each tier is a role with start and stop tasks. These tasks are tagged appropriately. Foo lists Apache and MySQL as its contained roles.
Starting the app is as simple as "ansible-playbook Foo.yml --tags=start". Stopping it is a matter of "ansible-playbook Foo.yml --tags=stop". The interesting part comes in because to start Foo, MySQL needs to start first. To shut down Foo, Apache needs to stop first. Without a home-grown hack, there doesn't appear to be any way to conditionally control the order of role specifications. The hack is to specify the roles twice, in reverse order, with an associated variable that the leaf-level start/stop tasks use to decide whether to actually fire or not (yes, it's ugly :-). This doesn't seem like a weird use case to me, so I'm hoping there's a more elegant solution that doesn't involve separate roles/playbooks for every action type (start/stop/install/etc.). On Tuesday, March 24, 2015 at 3:29:16 PM UTC-5, Michael Peters wrote: > > I don't know if this helps, but I usually use roles for configuration > management and use standalone playbooks for orchestration stuff. I've > just found it easier to have more control if I centralize certain > aspects (like say an application upgrade) in a single playbook instead > of spread around in different roles. But roles are super useful for > configuration management. > > Just my 2 pence... > > On Tue, Mar 24, 2015 at 4:22 PM, Jeff Sussna <[email protected] > <javascript:>> wrote: > > Dumb question re orchestrating the starting and stopping of tiered > services > > with ordering dependencies: > > > > Imagine tier A depends on tier B. To bring up the app, start B then A. > To > > bring it down, stop A then B. I can't figure out whether it's possible > to > > represent these relationships using roles without having to basically > > duplicate things so there is an A-stop role, a A-start role, a B-stop > role, > > and a B-start role. Have gotten close to figuring it out using > start/stop > > tags, but can't model to opposite ordering dependencies between start > and > > stop. > > > > Anyone else come up with an efficient reusable way to model this use > case? > > > > -- > > You received this message because you are subscribed to the Google > Groups > > "Ansible Project" group. > > To unsubscribe from this group and stop receiving emails from it, send > an > > email to [email protected] <javascript:>. > > To post to this group, send email to [email protected] > <javascript:>. > > To view this discussion on the web visit > > > https://groups.google.com/d/msgid/ansible-project/fee39d00-8c4f-4daf-b4eb-a02d5d4956ec%40googlegroups.com. > > > > For more options, visit https://groups.google.com/d/optout. > -- You received this message because you are subscribed to the Google Groups "Ansible Project" group. To unsubscribe from this group and stop receiving emails from it, send an email to [email protected]. To post to this group, send email to [email protected]. To view this discussion on the web visit https://groups.google.com/d/msgid/ansible-project/cd45fec5-7fd0-4da3-8156-76ddd50013e9%40googlegroups.com. For more options, visit https://groups.google.com/d/optout.
