Hashicorp Nomad: Submit a Job

今天来写最基本的提交工作(Submit a Job)

Submit

提交工作的指令: nomad job run hello-world.nomad
但提交後但你怎麽知道

• 改了一堆，改了甚麽?
• 几百行的code有没有漏改或改错?
• 现有worker node的资源够不够?
• 能不能让我测试一下?

Dry-run

所以有一个指令可以用来测试: nomad job plan hello-world.nomad
它会告诉你修改了那些地方，如下的例子:
我修改了image的版本，由"nginx:1.19.2" => "nginx:1.21",
dry-run的结果告诉我 All tasks successfully allocated.并显示修改了哪些地方

$ nomad job plan hello-world.nomad
+/- Job: "hello-world"
+/- Task Group: "webfront" (1 create/destroy update)
  +/- Task: "nginx" (forces create/destroy update)
    +/- Config {
      +/- image:            "nginx:1.19.2" => "nginx:1.21"
          port_map[0][web]: "80"
        }

Scheduler dry-run:
- All tasks successfully allocated.

Job Modify Index: 748164
To submit the job with version verification run:

nomad job run -check-index 748164 nginx.nomad

When running the job with the check-index flag, the job will only be run if the
job modify index given matches the server-side version. If the index has
changed, another user has modified the job and the plan's results are
potentially invalid.

check-index

Dry-run 成功後就可以提交工作了?
在团体开发的环境下，直接执行nomad job plan hello-world.nomad, 要怎麽确保执行的是当下的job呢?
可能下一秒别人就修改了job, 所以Nomad在每次dry-run後都会提供一个Job Modify Index,透过index来保证执行的是当下plan job後的的内容。
但如果在submit job之前，有人又做了plan job得到新的index,则会造成旧的index, submit无效。

Job Modify Index: 748164
To submit the job with version verification run:

nomad job run -check-index 748164 nginx.nomad