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https://github.com/tritondatacenter/mi-debian-hvm

Repo to create the machine image for debian images in the Joyent Cloud
https://github.com/tritondatacenter/mi-debian-hvm

debian

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Repo to create the machine image for debian images in the Joyent Cloud

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README 

        



# Debian Image Builder



This repo allows one to create custom Debian images for use with Triton.

Other [repositories](https://github.com/joyent?q=mi--hvm) provide equivalent

functionality for other distribution types.



## Requirements



In order to use this repo, you need to have a SmartOS "joyent" brand zone that

is capable of running qemu.  In order to run qemu the instance needs

customization beyond what can be done with Triton APIs.  That is, an operator

needs to customize the instance.  This is typically accomplished by running the

following commands on the appropriate compute node:



```

uuid=XXX	# Change this to the instance uuid



topds=zones/$uuid/data

zfs create -o zoned=on -o mountpoint=/data $topds



zonecfg -z $uuid <` image run:



```

# ./create-image -r 

```



```

$ ./create-image -h

Usage:

        ./create-image [options] [command ...]

option:

        -h          This message

        -r          Distro release



Commands:

        fetch       Fetch the installation ISO

        iso         Create a kickstart ISO

        image       Generate the image

```



### fetch



Download the distribution's netinst media (.iso) and verify its integrity.

If the required ISO already exists, its integrity is verified.  If it is found

to be corrupt it is fetched again.



This image will be automatically mounted at `/cdrom` during installation.



### iso



Generate an installer ISO image.  This will contain the following:



* `preseed.cfg` - From `debian-/preseed.cfg`.

* `sdc-vmtools` - The current content of the

  [sdc-vmtools](https://github.com/joyent/sdc-vmtools) repo.

* `early-command` - A preinstallation script, from

  `debian-/early-command`

* `late-command` - A postinstallation script, from

  `debian-/late-command`



This image is automatically mounted when the debian installer needs it, but is

not automatically mounted in the chroot (`/target`) while `late-command` is

running.  For that reason, each release's late command needs to mount it at

`/target/cdrom` prior to running `late-command`.



### image



This runs qemu in a way that allows unattended installation using the media

described above.  Once qemu exits, a Triton-compatible

image is generated and stored in the current `bits/` directory as

`debian--.{json,tar.gz}`.



The actual image creation is handled by `sdc-vmutils/bin/create-hybrid-image`.



### upload



This invokes

[bits-upload.sh](https://github.com/joyent/eng/blob/master/tools/bits-upload.sh)

to upload the image to manta and updates.joyent.com.



## Default Settings For Images



Each image has the following characteristics.  See

`debian-/preseed.cfg` for details on which packages are included.



* Disk is 10GB in size (8GB for / and the rest for swap)

* Stock Kernel

* US Keyboard and Language

* Firewall enabled with SSH allowed

* Timezone is set to UTC

* Console is on ttyS0

* Root password is blank: console login is allowed without a password

* Configuration from the SmartOS metadata service is performed using cloud-init.



## Development



The following serves as a guide for adding support for new Debian-like

distributions and versions of existing distributions.



Distribution-specific content is found in a per-distro subdirectory.  For

example, Debian 10 bits are in the `debian-10` directory.  Directory names are

always lower-case.



The following subsections describe the content that may be in a per-distro

directory.



### preseed.cfg file



The [preseed](https://wiki.debian.org/DebianInstaller/Preseed) configuration

file.  Notable parts of this include:



* `cloud-init` is installed, as it is responsible for interacting with the

  host's metadata service to configure networking, run user scripts, etc.  It

  requires `pyserial`, but for "reasons" the cloud-init developers have avoided

  adding pyserial as a dependency.

* `cloud-init` requires configuration in

  `/etc/cloud/cloud.cfg.d/90\_smartos.cfg` to only enable the SmartOS

  datasource, among other things.

* A `preseed/early\_command` (`debian-/early-command`) is used to tail

  the installation log and write it to `/dev/ttyS0`.  This script is run under

  busybox, so avoid the use of anything too fancy.  `qemu` runs in such a way

  that the guest's `ttyS0` appears on `qemu`'s `stdout`, thus allowing the

  installation log to be captured by Jenkins or similar automation that may be

  creating an image.

* A `preseed/late\_command` (`debian-/late-command`) runs at the end of

  the installation to perform the final tweaks on the image.  It runs chroot'd

  in the installed image.



The early and late command scripts need to communicate their successful

execution to `build-image`.  To do this, they need to emit

`JOYENT_STATUS_PRE=ok` (for early command) and `JOYENT_STATUS_POST=ok` (for late

command) to `/dev/ttyS0`.  `build-image` looks for these markers at the

beginning of a line.  The typical way to emit these markers is by adding the

following to the beginning of the script:



```

#! /bin/bash



joyent_status=fail

trap '(echo ""; echo JOYENT_STATUS_POST=$joyent_status; echo "") >>/dev/ttyS0' \

    EXIT



set -ex

```



and end with:



```

set +x

joyent_status=ok

```



`create-image` will verify that all `JOYENT_STATUS_` tags are set to `ok`,

which only happens if the script in that section runs to completion.



### keys directory



Each GPG key found in the keys directory will be imported into the keyring of

the user running this command.  These keys are used for authenticating the media

that is downloaded by the `fetch` command.



### create-image-overrides.sh



If the distribution requires overrides of any functionality, it should be added

here.  This file is sourced by `create-image` just before processing commands.

In general, the global variables that are all-uppercase are good candidates for

being overridden.



This file does not exist if not needed.