R Consulting Appliances Installation

R Consulting

R Consulting Appliances are pre-prepared, customized nanobsd system images.

They can be installed on a 4GB, or larger, SATA DOM, USB drive, SSD, or hard-disk drive. GPT layout is used to divide the storage device on two root file systems, a persistent configuration, and a persistent data partitions. Root file system is read-only in runtime, with /etc and /var directories being kept in RAM. As such, any change made in /etc must be explicitly saved or they will be lost upon system shutdown.

Installation

R Consulting Appliance is distributed as two files: a compressed disk image and this document. To install the disk image simply boot a live Unix OS on the target machine and execute

live# gunzip -c path/to/diskimage.gz | dd bs=131072 of=/dev/disk

On Linux disks are commonly named sda, sdb, etc.; information on which device matches to which disk can be found in boot messages (dmesg). On FreeBSD camcontrol devlist and geom disk list commands will list attached storage devices.

Configuration management

The cfg utility exists to manage /etc changes. Executing just cfg will list modified files. cfg save will list modified files and will ask whether to keep each change. cfg save -y will save changes unconditionally. For more information read cfg utility man page: man cfg.

Upgrades

Upgrades are shipped as compressed root file system images. Upgrade file can be downloaded to a remote Unix system, then the following command should be executed:

remote# cat path/to/rootimage.gz | ssh appliance img update -z

Upgrade can also be applied from the appliance itself:

appliance# img update -z https://dropbox.rconsulting.bg/nanobsd/...

img utility will write the OS upgrade into alt root file system partition and will instruct bootloader to boot from it upon next system startup. After system reboot, if upgraded OS image works, as intended, upgraded partition can be made persistently active using img commit. Otherwise rebooting the system will revert to previous root file system image.

Initial configuration migration/import

Appliance contains a script to migrate/import existing configuration and it is also available at https://dropbox.rconsulting.bg/nanobsd/migrate-cfg, for convenience. The script supports three ways of collecting the existing configuration: by running it on…

  1. … the target host before migration,

  2. … the target host after migration,

  3. … a local FreeBSD, accessing target host via ssh.

Let’s look at each point in more detail:

  1. To prepare things in advance, while OS to be replaced is still running, do the following:

    1. Attach the storage device, where nanobsd appliance software is to be installed, on the target host;

    2. Using the script, test if the existing configuration can be imported, like this: /path/to/migrate-cfg -t;

    3. Mount its configuration partition (use gpart show -lp to find the right one; it is usually addressable as /dev/ufs/cdncfg or /dev/gpt/cdncfg; /mnt is a “spare” place to do temporary mounts; example command would be mount /dev/gpt/cdncfg /mnt);

    4. Ask the script to import the existing configuration, like this: /path/to/migrate-cfg -d /mnt/etc (pay attention to /etc, following /mnt);

    5. Unmount configuration partition.

  2. To import existing configuration from a running appliance, do the following:

    1. Mount configuration partition from the OS to be replaced (see c. point above for pointers on how to locate legacy root filesystem); example command could be mount /dev/da0p2 /mnt;

    2. Using the script, test if the existing configuration can be imported, like this: /path/to/migrate-cfg -s /mnt/etc -t;

    3. Ask the script to import the existing configuration, like this: /path/to/migrate-cfg -s /mnt/etc -d /etc;

    4. Unmount legacy root filesystem.

  3. To import configuration from a remote OS via ssh follow same steps as the 1st case, but append -s remotehost: parameter to migrate-cfg (pay attention to the colon, following remotehost). Be aware, that ssh have to be configured to use pre-shared keys or the password will have to be typed multiple times.

Initial configuration checklist

The password for root account is initially blank. sshd (secure shell daemon) is configured to allow only pre-shared key authentication; using password-based login is, by default, disabled.

Management IP address is used for configuration and monitoring, and is part of the management subnet: an isolated, secured, private network, where each machine is assigned an IP address from (for example 192.168.123.0/24). Since not all servers should be visible from the Internet (transcoders export no public services), remote administration can be provided using port forwarding. However it is important this network to be isolated and secured, since lots of un-firewalled services are accessible within.

A R Consulting Appliance requires the following mandatory configuration steps, before it is fully active:

cfg utility is able to verify initial configuration, to an extent, with cfg test.

Resources