nbdserver

NBD Server for blocks stored in ARDB

Installing the NBD Server

Requires Go 1.8 or above.

Using github.com/zero-os/0-Disk/Makefile:

OUTPUT=$GOPATH/bin make nbdserver

or by simply using the Go toolchain:

go install github.com/zero-os/0-Disk/nbdserver

NBD Server Configuration

See the NBD Server Configuration docs for more information about how to configure the NBD Server.

Usage

⚠ NOTE ⚠

When using qemu to convert and emulate images hosted via an nbdserver, only qemu 2.8 is supported.

It is known and accepted that the nbdserver does not work when used with qemu 2.10 and any version other than 2.8. See issue #523 for more information.

When using nbd-client to connect to the nbdserver, only nbd-client version 3.10 is supported, it is known and accepted that the nbdserver does not work with nbd-client version 3.11 and above. See issue #523 for more information.

Use nbdserver -h or nbdserver --help to get more information about all available flags.

Example

Make sure you have an ARDB server(s) running, on the connection info specified in the used configured (using configuration stored in the etcd server running at myserver:2037).

make nbdserver && bin/nbdserver -protocol tcp -address ":6666" -config myserver:2037

Connect your nbd-client to the server running on localhost:6666:

sudo nbd-client -b 4096 -name default localhost 6666 /dev/nbd1
sudo mkfs.ext4 -b 4096 /dev/nbd1
sudo mount /dev/nbd1 /mnt/sharedvolume

Converting an image using 'qemu-img' to insert an image in the NBD server:

apt-get install qemu-utils

When the NBD server is running on a TCP socket:

qemu-img convert -p -n ubuntu-16.04-server-cloudimg-amd64-disk1.img -O nbd nbd+tcp://[HOST]:[PORT]/[VDISKID]

When the NBD server is running on a Unix socket:

qemu-img convert -p -n ubuntu-16.04-server-cloudimg-amd64-disk1.img -q nbd nbd+unix:///[VDISKID]?socket=/tmp/nbd-socket

More

For more verbose documentation see the /docs directory.

You'll find there following sections about the NBD Server:

• NBD Server Introduction
• Building your NBD Server
• NBD Server Configuration
• Using your NBD Server

For more information about the internals of the NBD Server you can find the following sections:

• The types of Backend Storage and how they work:
  • The Deduped Backend Storage (used for boot vdisks);
  • The Non Deduped Backend Storage (used for db and cache vdisks);