Comment 6 for bug 1991813

Hello,

While working on the upgrade to 22.04, I hit the same issue.

> what is the d-i solution here?

With 18.04 and 20.04, I use d-i preseed/early_command to write a general purpose run-parts hook:

```
  # Aptly repos are signed with ACME GPG key. Import Aptly keyring in the installer.
  d-i preseed/early_command string \
    wget -O /usr/share/keyrings/$breed-archive-keyring.gpg http://mirror.acme.tld/repos/acme/aptly-archive-keyring.gpg; \
    echo '#!/bin/sh' > /usr/lib/base-installer.d/09apt-key; \
    echo 'set -x' >> /usr/lib/base-installer.d/09apt-key; \
    echo 'set -e' >> /usr/lib/base-installer.d/09apt-key; \
    echo 'mkdir -p /target/etc/apt/trusted.gpg.d/' >> /usr/lib/base-installer.d/09apt-key; \
    echo 'cp /usr/share/keyrings/$breed-archive-keyring.gpg /target/etc/apt/trusted.gpg.d/aptly-archive-keyring.gpg' >> /usr/lib/base-installer.d/09apt-key; \
    chmod +x /usr/lib/base-installer.d/09apt-key
```

The commit message of this change in our codebase:

> The import of the keyring into the debian-installer does not imply that
> the keyring will be available in the system once installed. Inject a
> run-parts hook named `09apt-key` in the base-installer to copy the
> keyring to the appropriate location. This will allow to install the
> security updates during the installation process.

I searched through subiquity and curtin documentation but did not find how to mimic the run-parts hooks.

HtH