virt-bootstrap - Man Page

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virt-bootstrap is a tool providing an easy way to setup the root file system for libvirt-based containers. It allows to use either a tarball containing the file system, an image on a docker registry or virt-builder template and unpacks it either as a folder or in a

-f,  --format

Output format of the root file system. Possible values are dir (default) and qcow2.

--root-password SELECTOR

This argument will generate hash from ROOT_PASSWORD, gotten from the SELECTOR field, and insert the hashed value into /etc/shadow in the created root file system.

Note that SELECTOR can be one of the following: "file:".

If the output format is qcow2 these modifications are applied in additional qcow2 disk image.

Note that the /etc/shadow file must already exist in the extracted root file system of the container image and it must have entry for root user.

--no-cache

When this flag is used Docker images will be downloaded in temporary directory and discarded after the root file system is extracted.

--status-only

If this flag is used the log messages will be suppresses and only information about the current progress will be displayed.

-q,  --quiet

Show only warning and error messages.

-d,  --debug

Show debugging output messages.

-h,  --help

Display command line help summary.

--version

Show virt-bootstrap's version number and exit.

Create root file system using Ubuntu image docker.io registry:

    $ virt-bootstrap docker://ubuntu /tmp/foo

Create root file system from image stored on private Docker registry:

    $ virt-bootstrap docker://localhost:5000/ubuntu /tmp/foo \
      --username testuser \
      --password testpassoword \
      --not-secure

Apply UIDs/GIDs mapping for root file system entries

    $ virt-bootstrap docker://fedora /tmp/foo \
      --idmap 0:1000:10

This above command will map UIDs/GIDs: 0-9 to 1000-1009

The same result can be achieved with:

    $ virt-bootstrap docker://fedora /tmp/foo \
      --uidmap 0:1000:10 \
      --gidmap 0:1000:10

Multiple mapping values can be specified as follows:

    $ virt_bootstrap.py docker://ubuntu /tmp/foo \
      --idmap 0:1000:10 \
      --idmap 500:1500:10

This will map the UID/GIDs: 0-9 to 1000-1009 and 500-509 to 1500-1509

Set root password

    $ virt_bootstrap.py docker://opensuse /tmp/foo \
      --root-password file:/tmp/secret

The above command will download the opensuse container image and extract the root file system to /tmp/foo. Then it will generate hash of the password present in /tmp/secret file and insert it into /tmp/foo/etc/shadow file.

    $ virt_bootstrap.py docker://opensuse /tmp/foo \
      --root-password file:/tmp/secret \
      -f qcow2

Similarly for qcow2 format the container image will be downloaded and the root file system will be extracted into qcow2 disk images with backing chains. Then additional qcow2 image will be created with backing file set to the last layer and the modification of shadow file will be applied there.

Written by Cedric Bosdonnat and  Radostin Stoyanov