Re: Policy/Promise to agents

Thank you, I will give this a go.

On Tuesday, August 9, 2022 at 5:58:53 PM UTC-5 [email protected] 
wrote:

> Ugh, ignore the links to promises.cf and creat_a_file.cf, something is 
> trying to be helpful and make links to things that shouldn't be links.
>
> On Tuesday, August 9, 2022 at 5:57:11 PM UTC-5 Nick Anderson wrote:
>
>> Rakesh Patel <[email protected]> writes: 
>>
>> First new to cf CFengine. 
>>
>> Hi Rakesh, Welcome! I hope you enjoy your stay. 
>>
>> I have a sample file called creat_a_file.cf in the /var/cfengine/master 
>> directory on the hub server. 
>>
>> File content 
>>
>> Listing 1: File content
>>
>> #!/var/cfengine/bin/cf-agent --no-lock
>> body common control{
>> bundlesequence =>{"create_test_file"};}
>> bundle agent create_test_file{
>>     files:
>>             "/tmp/test-cfengine/test-file"
>>
>>             edit_line => addline,
>>             create => "true";}
>> bundle edit_line addline{
>>     insert_lines: "Cfengine is running nicely.";
>>
>> This policy above seems to have been truncated early (it's missing a 
>> trailing }, probably just a copy pasta error since you said that you get 
>> the output you expect if you run the file directly. 
>>
>> The file is copying to the agents but not executing. I can manually run 
>> the file and get the expected output but again not automatically. What am I 
>> missing. I have read that I need to modify the promise.cf file on the 
>> hub server but where and what? 
>>
>> What you read probably mentioned promises.cf (note the s). It's in the 
>> root of the policy set. promises.cf is the first policy file read by 
>> cfengine components if one is not specified. 
>>
>> However, that's rather old advice, at least if you are running the 
>> Masterfiles Policy Framework (MPF), which is the default policy set you get 
>> with CFEngine. 
>>
>> I assume you are running the MPF (documentation here 
>> <https://docs.cfengine.com/docs/master/reference-masterfiles-policy-framework.html>). 
>>
>>
>> Now, to what you are missing … 
>>
>> First, your snippet is written as a *standalone* policy. It's got a body 
>> common control and there can only be one of those per policy entry 
>> (policy entry is the first policy file read, e.g. promises.cf or 
>> whatever you give to -f or --file options to the component like cf-agent 
>> -f update.cf). So, if this policy file were included into the main 
>> policy (promises.cf) you would get errors. So, start by stripping out 
>> body common control from the file. Let's replace it with a library main 
>> bundle 
>> <https://docs.cfengine.com/docs/master/reference-language-concepts-bundles.html#library-main-bundles> 
>> ( bundle agent __main__, a bundle that gets called as part of the 
>> default bundlesequence if none is provided). In that bundle, let's add a methods 
>> type promise 
>> <https://docs.cfengine.com/docs/master/reference-promise-types-methods.html> 
>> to actuate your bundle agent create_test_file. 
>>
>> So, you end up with this: 
>> Listing 2: Example Policy
>>
>> #!/var/cfengine/bin/cf-agent --no-lockbundle agent __main__{
>>   methods:
>>       
>>
>> "create_test_file";}bundle agent create_test_file{
>>   files:
>>       "/tmp/test-cfengine/test-file"
>>         edit_line => addline,
>>         create => "true";}
>> bundle edit_line addline{
>>       insert_lines: "Cfengine is running nicely.";}
>>
>> Now, when you run the policy file directly it should still work as 
>> expected: 
>>
>>
>> # cf-agent --no-lock --log-level info --file /home/nickanderson/org/roam/daily/work/cfengine3-yn06AG
>>     info: Created directory for '/tmp/test-cfengine/test-file'
>>     info: Created file '/tmp/test-cfengine/test-file', mode 0600
>>     info: Inserted the promised line 'Cfengine is running nicely.' into '/tmp/test-cfengine/test-file' after locator
>>     info: insert_lines promise 'Cfengine is running nicely.' repaired
>>     info: Edited file '/tmp/test-cfengine/test-file'
>>
>> Note: Pay no attention to my filename there, it's just a temporary file 
>> that I stuck your policy into when I ran it with (ob-cfengine3 
>> <https://github.com/nickanderson/ob-cfengine3>) 
>>
>> Now, you want to include this policy file as part of your larger policy 
>> set (you want it to run with promises.cf runs). 
>>
>> For this I recommend using Augments 
>> <https://docs.cfengine.com/docs/master/reference-language-concepts-augments.html>. 
>> Create /var/cfengine/masterfiles/def.json with the following content. 
>>
>> {
>>     "inputs": [ "creat_a_file.cf" ],
>>     "vars": {
>>         "control_common_bundlesequence_end": [ "create_test_file" ]
>>     }}
>>
>> The *inputs* key is relative to the policy entry or a fully qualified 
>> path. You said you have creat_a_file.cf in /var/cfengine/masterfiles/. 
>> *masterfiles* is the *distribution* point. The update.cf policy copies 
>> things to /var/cfengine/inputs and the components 
>> <https://docs.cfengine.com/docs/master/reference-components-cf-monitord.html> 
>> all read from /var/cfengine/inputs by default. So here you would either 
>> specify /var/cfengine/inputs/creat_a_file.cf or simply creat_a_file.cf 
>> as shown. Also, the inputs key is used only by the promises.cf policy 
>> entry. 
>>
>> Next we defined control_common_bundlesequence_end this gets defined as 
>> default:def.control_common_bundlesequence_end (the default namespace, 
>> bundle def, variable control_common_bundlesequence_end). Which the MPF 
>> uses as the last entry in it's body common control bundlesequence 
>> <https://github.com/cfengine/masterfiles/blob/7bd864a8848180f3650940d4d353148083f8cfea/promises.cf.in#L61>. 
>> This tun-able is documented here 
>> <https://docs.cfengine.com/docs/master/reference-masterfiles-policy-framework.html#append-to-the-main-bundlesequence> 
>> in the Masterfiles Policy Framework section of the Reference MPF Reference. 
>>
>> Also, I know the agents update every 5 minutes, but how can I force to 
>> update it manually? 
>>
>> After you have made the above changes force a policy update (/var/cfengine/bin/cf-agent 
>> -KIf update.cf) then try a normal policy run, perhaps with -K (aka 
>> --no-lock) and -I (aka --inform, or --log-level=info). 
>>
>> I hope you find this helpful, good luck on your journey! 
>>
>> You might also enjoy the ongoing The Agent is In 
>> <https://www.youtube.com/watch?v=YYS1CUggomU&list=PLh71Vl9YjMaji_jnHFZ3k4mDbyOCE3A2x> 
>> series. 
>>
>

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