21.3. Running the Podman API manually

Procedure

1. Run the service for the REST API:

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

   • The value of 0 means no timeout. The default endpoint for a rootful service is unix:/run/podman/podman.sock.
   • The --log-level <level> option sets the logging level. The standard logging levels are debug, info, warn, error, fatal, and panic.

2. In another terminal, display system information of Podman. The podman-remote command, unlike the regular podman command, communicates through the Podman socket:

   # podman-remote info

3. To troubleshoot the Podman API and display request and responses, use the curl comman. To get the information about the Podman installation on the Linux server in JSON format:

   # curl -s --unix-socket /run/podman/podman.sock http://d/v1.0.0/libpod/info | jq
       {
     "host": {
       "arch": "amd64",
       "buildahVersion": "1.15.0",
       "cgroupVersion": "v2",
       "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"
     }
   }

   A jq utility is a command-line JSON processor.

4. Pull the registry.access.redhat.com/ubi10/ubi container image:

   # curl -XPOST --unix-socket /run/podman/podman.sock -v 'http://d/v1.0.0/images/create?fromImage=registry.access.redhat.com%2Fubi10%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%2Fubi10%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/ubi10/ubi:latest, registry.redhat.io/ubi10/ubi:latest","error":"","progress":"","progressDetail":{},"id":"ecbc6f53bba0d1923ca9e92b3f747da8353a070fccbae93625bd8b47dbee772e"}
   * Connection #0 to host d left intact

5. Display the pulled image:

   # 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/ubi10/ubi:latest", "registry.redhat.io/ubi10/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": "ubi10", ... "summary": "Provides the latest release of Red Hat Universal Base Image 8.", "url": "https://access.redhat.com/containers//registry.access.redhat.com/ubi10/images/8.2-347",
         ...
       },
       "Names": [
         "registry.access.redhat.com/ubi10/ubi:latest",
         "registry.redhat.io/ubi10/ubi:latest"
       ],
       ...
       ]
     }
   ]