Ability to exec processes in background mode #22

qk4l · 2018-08-11T18:35:17Z

Hi,

I'm looking on remco as a configuration manage tool inside containers for our cloud infrastructure.
We are using system OS containers with several applications inside and systemd is used as an init system.

remco is starting as a daemon before any services for which configs should be generated.
But here is a problem - there is not option to detect if remco's resources have been successfully proceed and services could be start.

To resolve this there is exec option (command) but it require foreground mode which is not suitable for systemd services. =(
Also I do not like an idea to run services in foreground mode because they will be killed if remco failed and died. It's ok if remco is used as a supervisor or init system (proc 1) but decrease reliability if it works as configuration management tool only.

I suggest to add additional option and allow to exec processes in background mode.

The text was updated successfully, but these errors were encountered:

HeavyHorst · 2018-08-12T14:53:30Z

Isn't the check and reload commands what you need?
https://heavyhorst.github.io/remco/details/commands/

qk4l · 2018-08-12T15:16:59Z

Hi, unfortunately no. :( As I understand reload_cmd command can not be used as start_cmd. I want to do something like that: exec: systemctl start $name ... reload_cmd: systemctl reload $name This will be prevent program $name to die if remco will have been restarted and allow to start $name just after recmo have finished his work not before.

HeavyHorst · 2018-08-12T16:15:50Z

I've added a start_cmd option.
The start command is executed only once at startup. If no start command is specified, the behavior is the same as before.

The config looks like:

  [[template]]
    src         = "/etc/remco/templates/test.cfg"
    dst         = "/home/rkaufmann/Downloads/remcotest"
    mode        = "0644"
    start_cmd  = "echo 'start'"
    reload_cmd = "echo 'reload'"

Could you try this with latest master to see if that works for you?

qk4l · 2018-08-12T16:18:59Z

Oh, it's great! I'll try as soon as I see my laptop. =)

On Sun, Aug 12, 2018, 7:15 PM Rene Kaufmann ***@***.***> wrote: I've added a start_cmd option. The start command is executed only once at startup. If no start command is specified, the behavior is the same as before. The config looks like: [[template]] src = "/etc/remco/templates/test.cfg" dst = "/home/rkaufmann/Downloads/remcotest" mode = "0644" start_cmd = "echo 'start'" reload_cmd = "echo 'reload'" Could you try this with latest master to see if that works for you? — You are receiving this because you authored the thread. Reply to this email directly, view it on GitHub <#22 (comment)>, or mute the thread <https://github.com/notifications/unsubscribe-auth/AIAVS8waIhUWbI74LazXZPYqYxToNyOTks5uQFS2gaJpZM4V5RDf> .

-- Best regards, Artyom

qk4l · 2018-08-12T16:25:25Z

If start_cmd is a part of template it is not possible to define several templates for single app. It's a reason why I thought to define it in exec array. If templates is single resource generates in defined order?

On Sun, Aug 12, 2018, 7:15 PM Rene Kaufmann ***@***.***> wrote: I've added a start_cmd option. The start command is executed only once at startup. If no start command is specified, the behavior is the same as before. The config looks like: [[template]] src = "/etc/remco/templates/test.cfg" dst = "/home/rkaufmann/Downloads/remcotest" mode = "0644" start_cmd = "echo 'start'" reload_cmd = "echo 'reload'" Could you try this with latest master to see if that works for you? — You are receiving this because you authored the thread. Reply to this email directly, view it on GitHub <#22 (comment)>, or mute the thread <https://github.com/notifications/unsubscribe-auth/AIAVS8waIhUWbI74LazXZPYqYxToNyOTks5uQFS2gaJpZM4V5RDf> .

-- Best regards, Artyom

HeavyHorst · 2018-08-12T17:10:47Z

Youre right.
I moved the start_cmd to the resource configuration.
I'ts only executed after all templates are processed without errors.

   name = "someName"
   start_cmd  = "echo 'start'"
   [[template]]
     src         = "/etc/remco/templates/test.cfg"
     dst         = "/home/rkaufmann/Downloads/remcotest"
     mode        = "0644"
     reload_cmd = "echo 'reload'"

HeavyHorst · 2018-08-13T07:12:57Z

Maybe a reload_command at the resource level would also make sense.
This would be executed as soon as one of the templates changes (like the reload_signal in exec mode).

What do you think?

qk4l · 2018-08-13T10:58:44Z

I've tested start_cmd but it not works.

# /usr/bin/remco -version
remco Version: 0.10.0
UTC Build Time: 2018-08-13 09:01:49
Git Commit Hash: 9eda77c9d22417a23c70d3bafa6dd47862bcd95c
Go Version: go1.10.1
Go OS/Arch: linux/amd64

resource.d/nginx.toml

name = 'nginx'
start_cmd = "systemctl start nginx"

[[template]]
  src        = "/etc/remco/test.tmpl"
  dst        = "/etc/test_remco"
  reload_cmd = "systemctl reload nginx"

[0000]  INFO /usr/bin/remco[29255]: loading resource configuration path=/etc/remco/resource.d/nginx.toml
[0000]  INFO /usr/bin/remco[29255]: [creating pid file at "/var/run/remco.pid"]
[0000] DEBUG /usr/bin/remco[29255]: retrieving keys backend=env key_prefix= resource=nginx
[0000] DEBUG /usr/bin/remco[29255]: compiling source template resource=nginx template=/etc/remco/test.tmpl
[0000] DEBUG /usr/bin/remco[29255]: comparing staged and dest config files dest=/etc/test_remco resource=nginx staged=.test_remco041936203
[0000]  INFO /usr/bin/remco[29255]: target config out of sync config=/etc/test_remco resource=nginx
[0000] DEBUG /usr/bin/remco[29255]: overwriting target config config=/etc/test_remco resource=nginx
[0000] DEBUG /usr/bin/remco[29255]: Running systemctl reload nginx resource=nginx
[0000] ERROR /usr/bin/remco[29255]: "Job for nginx.service invalid.\n" resource=nginx
[0000] ERROR /usr/bin/remco[29255]: createStageFileAndSync failed: sync files failed: reload command failed: the reload command failed: exit status 1 resource=nginx
[0000] ERROR /usr/bin/remco[29255]: not all templates could be rendered, trying again after 20 seconds resource=nginx

It seems that start_cmd is not processing
reload_cmd should not be triggered if start_cmd was called.

Maybe a reload_command at the resource level would also make sense.
This would be executed as soon as one of the templates changes (like the reload_signal in exec mode).

Great idea! I think there are cases when one template required a reload and other one does not, so it's better to make reload_cmd at the resource level optional and save it in template array.

This allow to define reload_cmd globally for resource and avoid duplicates but still save flexibility for each template.

HeavyHorst · 2018-08-13T11:14:24Z

Hm, the start_cmd is only executed after all templates are processed without errors.
The reload_cmd is a part of the template processing.

I will change the code so that the reload_cmd is not called if a start_cmd is provided (only at startup obviously).

Great idea! I think there are cases when one template required a reload and other one does not, so it's better to make reload_cmd at the resource level optional and save it in template array.

I plan to keep both reload commands: one per template for fine grained control and one on the resource level. Both are optional.

Thank you for your help!

qk4l · 2018-08-13T12:05:03Z

Hm, the start_cmd is only executed after all templates are processed without errors.
The reload_cmd is a part of the template processing.

# /usr/bin/remco -config config.toml
[0000]  INFO /usr/bin/remco[49211]: loading resource configuration path=/etc/remco/resource.d/nginx.toml
[0000]  INFO /usr/bin/remco[49211]: [creating pid file at "/var/run/remco.pid"]
[0000] DEBUG /usr/bin/remco[49211]: retrieving keys backend=env key_prefix= resource=nginx
[0000] DEBUG /usr/bin/remco[49211]: compiling source template resource=nginx template=/etc/remco/test.tmpl
[0000] DEBUG /usr/bin/remco[49211]: comparing staged and dest config files dest=/etc/test_remco resource=nginx staged=.test_remco915523972
[0000]  INFO /usr/bin/remco[49211]: target config out of sync config=/etc/test_remco resource=nginx
[0000] DEBUG /usr/bin/remco[49211]: overwriting target config config=/etc/test_remco resource=nginx
[0000] DEBUG /usr/bin/remco[49211]: Running echo reload nginx resource=nginx
[0000] DEBUG /usr/bin/remco[49211]: "reload nginx\n" resource=nginx
[0000]  INFO /usr/bin/remco[49211]: target config has been updated config=/etc/test_remco resource=nginx

Even if template's render have finished successful start_cmd does not execute.

HeavyHorst · 2018-08-13T12:14:28Z

Are you sure that you're using the latest master branch?

cat /etc/remco/resource.d/test.toml

  name = "haproxy"
  start_cmd  = "echo 1"
  [[template]]
    src         = "/etc/remco/templates/test.cfg"
    dst         = "/home/rkaufmann/Downloads/remcotest"
    mode        = "0644"
    reload_cmd = "echo 'reload'"

  [backend]
    [backend.file]
      filepath = "/etc/remco/test.yml"
      watch    = true
      keys     = ["/"]

[0000]  INFO remco[8264]: loading resource configuration path=/etc/remco/resource.d/test.toml
[0000]  INFO remco[8264]: set file path backend=file filepath=/etc/remco/test.yml
[0000] DEBUG remco[8264]: retrieving keys backend=file key_prefix= resource=haproxy
[0000] DEBUG remco[8264]: compiling source template resource=haproxy template=/etc/remco/templates/test.cfg
[0000] DEBUG remco[8264]: comparing staged and dest config files dest=/home/rkaufmann/Downloads/remcotest resource=haproxy staged=.remcotest060591536
[0000]  INFO remco[8264]: target config out of sync config=/home/rkaufmann/Downloads/remcotest resource=haproxy
[0000] DEBUG remco[8264]: overwriting target config config=/home/rkaufmann/Downloads/remcotest resource=haproxy
[0000] DEBUG remco[8264]: Running echo 'reload' resource=haproxy
[0000] DEBUG remco[8264]: "reload\n" resource=haproxy
[0000]  INFO remco[8264]: target config has been updated config=/home/rkaufmann/Downloads/remcotest resource=haproxy
[0000] DEBUG remco[8264]: Running echo 1 resource=haproxy
[0000] DEBUG remco[8264]: "1\n" resource=haproxy
^C[0003]  INFO remco[8264]: Captured interrupt. Exiting...
[0003] DEBUG remco[8264]: closing client connection backend=file resource=haproxy

qk4l · 2018-08-13T13:33:48Z

Yes, just have recompiled. =(

# /usr/bin/remco -version
remco Version: 0.10.0
UTC Build Time: 2018-08-13 13:18:09
Git Commit Hash: 9eda77c9d22417a23c70d3bafa6dd47862bcd95c
Go Version: go1.10.1
Go OS/Arch: linux/amd64

Latest commit - 9eda77c

HeavyHorst · 2018-08-13T13:49:24Z

What is the exact content of /etc/remco/resource.d/nginx.toml?

qk4l · 2018-08-13T14:21:59Z

I simplify it as I can.

Here is tar with compiled remco and config directory.
remco.tar.gz

Something is wrong here =(

HeavyHorst · 2018-08-13T14:34:46Z

Your file doesn't work for me either.
Is your remco source by any chance not in $GOPATH/src/github.com/HeavyHorst/remco/cmd/remco?

Thats always the path the buildscript uses.
You could build it without the script:

go build github.com/qk4l/remco/cmd/remco

HeavyHorst · 2018-08-13T14:37:21Z

All import paths are like this: github.com/HeavyHorst/remco/pkg/template
It'd be the easiest thing if you worked from there.

HeavyHorst · 2018-08-13T14:47:33Z

I've also added the mentionend reload command.

I will change the code so that the reload_cmd is not called if a start_cmd is provided (only at startup obviously).

Also done.

let me know if you have any more problems building the source.

qk4l · 2018-08-13T15:06:38Z

Oh, sorry, my mistake.
I should read more about golang building.

I've tested reload_cmd and start_cmd. Everything woks as expected.

Thank you very much!

HeavyHorst · 2018-08-13T15:18:30Z

Great! I will leave this issue open until i've added the documentation.

LanceKroepke · 2018-10-12T22:26:45Z

@HeavyHorst DOCU PLS?!

HeavyHorst closed this as completed Dec 10, 2018

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Ability to exec processes in background mode #22

Ability to exec processes in background mode #22

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Ability to exec processes in background mode #22

Ability to exec processes in background mode #22

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