If I may chime in. Ansible is a tool for configuration management which has been aptly been explained but I will explain further to give some detail . The second use case is orchestration.
If you program say with a script you tell it what to do. You have to control from the start to finish the logic what to do. It is in order. When you use ansible you don't have to program. You just say I want this thing to look like this and it will do it. But ansible can put things in order too in other words orchestration. This becomes powerful because it allows people to write what could be otherwise complex code into something that is concise. On Sat, 19 Jun 2021 at 9:11 AM jane p <[email protected]> wrote: > Anthony, > thank you for your response. > > Would you mind addressing the scenarios and implementation options of > installing/updating the system? > I think there is a conflict between the virtue of avoiding state > changes on consecutive runs, and simplicity in implementation. > > Thank you for the example of targeting multiple hosts with a single > playbook, with different results for each host. > A playbook that doesn't do state changes scales better when running > against multiple hosts. > > On Fri, Jun 18, 2021 at 3:34 PM Antony Stone > <[email protected]> wrote: > > > > On Friday 18 June 2021 at 22:17:30, Jane Prusakova wrote: > > > > > I am new to Ansible, and am trying to understand its best practices. > My > > > team uses Ansible for system setup and product deployment. > > > > > > I am reading that idempotance is the foundational virtue, where > playbook > > > idempotence is defined as not doing any state changes on consecutive > runs. > > > I am not sure I understand why. > > > > For me, the reason is simple - you want to be able to run ansible > multiple > > times on a given machine and be confident that the state it is left in > > afterwards is the same every time. > > > > Suppose you have a machine which does not have a web server installed on > it, > > and you have an ansible playbook which installs and configures the web > server. > > > > You want to be able to run that playbook once, and end up with a working > web > > server. > > > > You want to be able to run that smae playbook again (with no changes) > and have > > the same working web server (with no changes) on the target machine. > > > > This is partly because playbooks are often nested, so that you might > have one > > for a web server and another for a mail server; you modify the one for > the > > mail server but then run both of them; you want the modification you > made to > > the mail server playbook to take effect but you want the web server on > the > > target machine to stay just the way it was after the first run of the > playbook. > > > > > Appreciate any thoughts on why avoiding state changes on consecutive > > > playbook runs is preferred over simplicity and robustness in > > > implementation. > > > > Is that a quote from somewhere? Is there anywhere in either the ansible > > documentation or any tutorials / online guidelines you have read which > say > > that "avoiding state changes on consecutive playbook runs is preferred > over > > simplicity and robustness in implementation"? > > > > Idempotence (avoiding state changes on consecutive runs) is essential. > > > > Simplicity, and robustness in implementation, are highly desirable. > > > > Is there a conflict between the two? > > > > > > Antony. > > > > -- > > Archaeologists have found a previously-unknown dinosaur which seems to > have > > had a very large vocabulary. They've named it The Saurus. > > > > Please reply to the > list; > > please *don't* > CC me. > > -- > 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 view this discussion on the web visit > https://groups.google.com/d/msgid/ansible-project/CAGB%3D%3DuLXscYNsgqdYXq389XhjUAB3_vf0ErFfwiUek%3DAqBB_HQ%40mail.gmail.com > . > -- 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 view this discussion on the web visit https://groups.google.com/d/msgid/ansible-project/CA%2BjXPxgd-3pyKJfPryCfQ5ztBpxoOq%2BOYimhh%3DjUsVwRotLfpw%40mail.gmail.com.
