docs: extend the unattended install docs

[imobachgs]

Extend the unattended installation documentation. You can check the preview.

This is a first step toward having a decent documentation. It includes:

• Description of most of the elements in the profile.
• Reorganization of the whole "Unattended installation" section.

We could argue that loading/exporting a profile is not limited to the unattended installation. But we could agree that, at this point, both topics are closely related.

Formatting

I have formatted the files using prettier:

$ npx prettier --write --prose-wrap always --print-width 100 $FILE

[jreidinger]

maybe I would explain here that if there is need for specific kernel parameter for kernel already for installation, then it will be reused in proposal. So it is mainly for parameters that are only for installed system and not installation.

[imobachgs]

I did not get it, sorry.

[ancorgs]

I commented some small things. Overall this is an outstanding work!

[jreidinger]

I would welcome here what can be options. Probably link to NM documentation.

[imobachgs]

I am not sure whether the NetworkManager documentation will help here.

[jreidinger]

now after merge of extraRepositories it is three of them. Feel free to add it to this PR or I can add it separately. As I will need to enhance when new keys for GPG will be added.

[imobachgs]

I can add it later, no problem.

[mvidner]

Thank you! I have some corrections and improvements.

[mvidner]

The docs is fine but let me take this opportunity to show that while I am validating all the examples in this PR, I have found a bug in the recent users PR.

The first object is what I paste in, the second one is agama output:

cc153869b9da:/checkout # agama config generate -
{
  user: {
    fullName: "Jane Doe",
    userName: "jane.doe",
    password: "123456"
  }
}

{
  "user": {
    "fullName": "Jane Doe",
    "userName": "jane.doe"
  }
}
✗ The profile is not valid. Please, check the following errors:

        * "password" is a required property. /user

✗ Internal error: the profile was made invalid by InstallSettings round trip

Including hashedPassword: false would hide the bug.

[imobachgs]

OK, I will check it.

[mvidner]

NP: openssl.rpm is IMHO more likely to be installed than whois.rpm

[imobachgs]

I did not write the original text, so I just moved from elsewhere. For me it is fine is someone comes with a proposal. :-)

[mvidner]

JFYI, the InstallSettings round trip makes the remaining attributes explicit:

cc153869b9da:/checkout # agama config generate -
{
  files: [
    {
      url: "/motd",
      destination: "/etc/issue.d/welcome.issue",
      permissions: "0644",
    },
    {
      destination: "/etc/sysusers.d/myapp.conf",
      content: |||
        # Type Name ID GECOS Home
        u      myapp - "My Application" /var/lib/myapp
      |||
    }
  ]
}
{
  "files": [
    {
      "url": "file:///motd",
      "permissions": "0644",
      "user": "root",
      "group": "root",
      "destination": "/etc/issue.d/welcome.issue"
    },
    {
      "content": "# Type Name ID GECOS Home\nu      myapp - \"My Application\" /var/lib/myapp\n",
      "permissions": "0644",
      "user": "root",
      "group": "root",
      "destination": "/etc/sysusers.d/myapp.conf"
    }
  ]
}
✓ The profile is valid.

[imobachgs]

Which is wrong, although out of scope. We have the same problem in several places.

[mvidner]

I was curious so I checked: not even Jsonnet can represent binary data, which makes sense once you realize it needs a JSON representation.

[mvidner]

JFYI, with /testing_using_container.sh, this fails because there are no disks, and we may want to improve the error formatting:

cc153869b9da:/checkout # agama config generate -
// There are included also helpers to search this hardware tree. To see helpers check
// "/usr/share/agama-cli/agama.libsonnet"
local agama = import 'hw.libsonnet';

// Find the biggest disk which is suitable for installing the system.
local findBiggestDisk(disks) =
  local sizedDisks = std.filter(function(d) std.objectHas(d, 'size'), disks);
  local sorted = std.sort(sizedDisks, function(x) -x.size);
  sorted[0].logicalname;
// ^ sorted[0] makes it fail
...
{
  product: {...  },
...,
}
Error: Backend call failed with status 400 and text '{"error":"Could not evaluate the profile: Jsonnet evaluation failed:\nRUNTIME ERROR: Index 0 out of bounds, not within [0, 0)\n\tprofile.jsonnet:9:3-12\t\n\tprofile.jsonnet:34:17-73\tobject <anonymous>\n\tField \"search\"\t\n\tArray element 0\t\n\tField \"drives\"\t\n\tField \"storage\"\t\n\tDuring manifestation\t\n\n"}'

[mvidner]

LGTM now

[ancorgs]

All my (small) objections were addressed. So this LGTM.