12.3. Ejecución manual de la API de Podman

Procedimiento

1. Ejecute el servicio para la API REST:

   # podman system service -t 0 --log-level=debug

   • El valor 0 significa que no hay tiempo de espera. El punto final por defecto para un servicio rootful es unix:/run/podman/podman.sock.
   • La opción --log-level <level> establece el nivel de registro. Los niveles de registro estándar son debug, info, warn, error, fatal y panic.

2. En otro terminal, muestra la información del sistema de Podman. El comando podman-remote, a diferencia del comando normal podman, se comunica a través del socket de Podman:

   # podman-remote info

3. Para solucionar los problemas de la API de Podman y mostrar las peticiones y respuestas, utilice el comando curl. Para obtener la información sobre la instalación de Podman en el servidor Linux en formato JSON:

   # curl -s --unix-socket /run/podman/podman.sock http://d/v1.0.0/libpod/info | jq
       {
     "host": {
       "arch": "amd64",
       "buildahVersion": "1.15.0",
       "cgroupVersion": "v1",
       "conmon": {
         "package": "conmon-2.0.18-1.module+el8.3.0+7084+c16098dd.x86_64",
         "path": "/usr/bin/conmon",
         "version": "conmon version 2.0.18, commit: 7fd3f71a218f8d3a7202e464252aeb1e942d17eb"
       },
       …
     "version": {
       "APIVersion": 1,
       "Version": "2.0.0",
       "GoVersion": "go1.14.2",
       "GitCommit": "",
       "BuiltTime": "Thu Jan  1 01:00:00 1970",
       "Built": 0,
       "OsArch": "linux/amd64"
     }
   }

   La utilidad jq es un procesador JSON de línea de comandos.

4. Extraiga la imagen del contenedor registry.access.redhat.com/ubi8/ubi:

   # curl -XPOST --unix-socket /run/podman/podman.sock -v 'http://d/v1.0.0/images/create?fromImage=registry.access.redhat.com%2Fubi8%2Fubi'
   *   Trying /run/podman/podman.sock...
   * Connected to d (/run/podman/podman.sock) port 80 (#0)
   > POST /v1.0.0/images/create?fromImage=registry.access.redhat.com%2Fubi8%2Fubi HTTP/1.1
   > Host: d
   > User-Agent: curl/7.61.1
   > Accept: /
   >
   < HTTP/1.1 200 OK
   < Content-Type: application/json
   < Date: Tue, 20 Oct 2020 13:58:37 GMT
   < Content-Length: 231
   <
   {"status":"pulling image () from registry.access.redhat.com/ubi8/ubi:latest, registry.redhat.io/ubi8/ubi:latest","error":"","progress":"","progressDetail":{},"id":"ecbc6f53bba0d1923ca9e92b3f747da8353a070fccbae93625bd8b47dbee772e"}
   * Connection #0 to host d left intact

5. Muestra la imagen extraída:

   # curl --unix-socket /run/podman/podman.sock -v 'http://d/v1.0.0/libpod/images/json' | jq
   *   Trying /run/podman/podman.sock...
     % Total    % Received % Xferd  Average Speed   Time    Time     Time  Current
                                    Dload  Upload   Total   Spent    Left  Speed
     0     0    0     0    0     0      0      0 --:--:-- --:--:-- --:--:--     0* Connected to d (/run/podman/podman.sock) port 80 (0) > GET /v1.0.0/libpod/images/json HTTP/1.1 > Host: d > User-Agent: curl/7.61.1 > Accept: / > < HTTP/1.1 200 OK < Content-Type: application/json < Date: Tue, 20 Oct 2020 13:59:55 GMT < Transfer-Encoding: chunked < { [12498 bytes data] 100 12485 0 12485 0 0 2032k 0 --:--:-- --:--:-- --:--:-- 2438k * Connection #0 to host d left intact [ { "Id": "ecbc6f53bba0d1923ca9e92b3f747da8353a070fccbae93625bd8b47dbee772e", "RepoTags": [ "registry.access.redhat.com/ubi8/ubi:latest", "registry.redhat.io/ubi8/ubi:latest" ], "Created": "2020-09-01T19:44:12.470032Z", "Size": 210838671, "Labels": { "architecture": "x86_64", "build-date": "2020-09-01T19:43:46.041620", "com.redhat.build-host": "cpt-1008.osbs.prod.upshift.rdu2.redhat.com", ... "maintainer": "Red Hat, Inc.", "name": "ubi8", ... "summary": "Provides the latest release of Red Hat Universal Base Image 8.", "url": "https://access.redhat.com/containers//registry.access.redhat.com/ubi8/images/8.2-347",
         ...
       },
       "Names": [
         "registry.access.redhat.com/ubi8/ubi:latest",
         "registry.redhat.io/ubi8/ubi:latest"
       ],
       ...
       ]
     }
   ]