Should groups be "exclusive"?

[davecb]

In a test, I got the message AddHost() failed: host p1s10.dcaux.indexww.com exists in multiple groups: zookeeper-nodes, dc1-stats, line: 1091

The machine was supposed to be in two groups, dc1-stats, with a specific task of providing zookeeper services, and our ansible seem to process it correctly.

Should the library be alerting on this?

[greenpau]

Should the library be alerting on this?

@davecb, you probably right! 👍 could you please share your inventory file? I will add it as one of test cases.

[davecb]

Sure: I renamed the host machines a bit, so the error is now
AddHost() failed: host p1s10.dcauxbozotron.com exist in multiple groups: zookeeper-nodes, dc1-stats, line: 1091

[davecb]

I had to rename the file, too (:-))
hosts.txt

[greenpau]

AddHost() failed: host p1s10.dcauxbozotron.com exist in multiple groups: zookeeper-nodes, dc1-stats, line: 1091

@davecb , initially, when I designed it, I thought that a host would exist in a single group. The way someone would make it a part of two or more groups is by group nesting. Now, imagine you have the same host in multiple groups, but each instance of host has different key-values associated with it. Which environment variables the host would inherit? i.e. group 1, group 2, or both?

What are your thoughts?

[davecb]

I spoke with My Smarter Colleagues, and we used nesting a lot, as well as assigning machines to multiple groups. Ansible handles it "properly", in this case meaning it delivers the information to the roles that use one or the other set of groups. If it didn't, we would have had one the other set fail. What the Ansible authors think of this I don't know: it may be a dysfunction that they haven't experienced, or it might be something they think is fine. In the latter case, they'd be thinking "Dave doesn't need to say 'x but not y' in the hosts files, just 'x and y'", where I'm using "and" in the ordinary English-language sense, not the formal-logic sense (;-)) The observed behavior suggests they think it's fine, and that we can have machines in multiple non-nested groups.

…

--dave On 2019-04-03 3:18 p.m., Paul G. wrote: AddHost() failed: host p1s10.dcauxbozotron.com exist in multiple groups: zookeeper-nodes, dc1-stats, line: 1091 @davecb<https://github.com/davecb> , initially, when I designed it, I thought that a host would exist in a single group. The way someone would make it a part of two or more groups is by group nesting. Now, imagine you have the same host in multiple groups, but each instance of host has different key-values associated with it. Which environment variables the host would inherit? i.e. group 1, group 2, or both? What are your thoughts? — You are receiving this because you were mentioned. Reply to this email directly, view it on GitHub<#1 (comment)>, or mute the thread<https://github.com/notifications/unsubscribe-auth/AAiJkYWWY54ZX1X8q9BH__i58BfA_nR1ks5vdP6JgaJpZM4cWAIY>.

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[greenpau]

The observed behavior suggests they think it's fine, and that we can have machines in multiple non-nested groups.

@davecb , 👍 will make necessary adjustments.