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garage/doc/book/src/cookbook/real_world.md
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Deploying Garage on a real-world cluster

To run Garage in cluster mode, we recommend having at least 3 nodes. This will allow you to setup Garage for three-way replication of your data, the safest and most available mode avaialble.

We recommend first following the quick start guide in order to get familiar with Garage's command line and usage patterns.

Get a Docker image

Our docker image is currently named lxpz/garage_amd64 and is stored on the Docker Hub. We encourage you to use a fixed tag (eg. v0.3.0) and not the latest tag. For this example, we will use the latest published version at the time of the writing which is v0.3.0 but it's up to you to check the most recent versions on the Docker Hub.

For example:

sudo docker pull lxpz/garage_amd64:v0.3.0

Generating TLS certificates

You first need to generate TLS certificates to encrypt traffic between Garage nodes (reffered to as RPC traffic).

To generate your TLS certificates, run on your machine:

wget https://git.deuxfleurs.fr/Deuxfleurs/garage/raw/branch/main/genkeys.sh
chmod +x genkeys.sh
./genkeys.sh

It will creates a folder named pki/ containing the keys that you will used for the cluster.

Deploying and configuring Garage

To run a real-world deployment, make sure you the following conditions are met:

  • You have at least three machines with sufficient storage space available

  • Each machine has a public IP address which is reachable by other machines. Running behind a NAT is possible, but having several Garage nodes behind a single NAT is slightly more involved as each will have to have a different RPC port number (the local port number of a node must be the same as the port number exposed publicly by the NAT).

  • Ideally, each machine should have a SSD available in addition to the HDD you are dedicating to Garage. This will allow for faster access to metadata and has the potential to drastically reduce Garage's response times.

Before deploying garage on your infrastructure, you must inventory your machines. For our example, we will suppose the following infrastructure with IPv6 connectivity:

Location Name IP Address Disk Space
Paris Mercury fc00:1::1 1 To
Paris Venus fc00:1::2 2 To
London Earth fc00:B::1 2 To
Brussels Mars fc00:F::1 1.5 To

On each machine, we will have a similar setup, especially you must consider the following folders/files:

  • /etc/garage/garage.toml: Garage daemon's configuration (see below)
  • /etc/garage/pki/: Folder containing Garage certificates, must be generated on your computer and copied on the servers
  • /var/lib/garage/meta/: Folder containing Garage's metadata, put this folder on a SSD if possible
  • /var/lib/garage/data/: Folder containing Garage's data, this folder will grows and must be on a large storage, possibly big HDDs.
  • /etc/systemd/system/garage.service: Service file to start garage at boot automatically (defined below, not required if you use docker)

A valid /etc/garage/garage.toml for our cluster would be:

metadata_dir = "/var/lib/garage/meta"
data_dir = "/var/lib/garage/data"

replication_mode = "3"

rpc_bind_addr = "[::]:3901"

bootstrap_peers = [
  "[fc00:1::1]:3901",
  "[fc00:1::2]:3901",
  "[fc00:B::1]:3901",
  "[fc00:F::1]:3901",
]

[rpc_tls]
ca_cert = "/etc/garage/pki/garage-ca.crt"
node_cert = "/etc/garage/pki/garage.crt"
node_key = "/etc/garage/pki/garage.key"

[s3_api]
s3_region = "garage"
api_bind_addr = "[::]:3900"

[s3_web]
bind_addr = "[::]:3902"
root_domain = ".web.garage"
index = "index.html"

Please make sure to change bootstrap_peers to your IP addresses!

Check the configuration file reference documentation to learn more about all available configuration options.

Starting Garage using Docker

On each machine, you can run the daemon with:

docker run \
  -d \
  --name garaged \
  --restart always \
  --network host \
  -v /etc/garage/pki:/etc/garage/pki \
  -v /etc/garage/garage.toml:/garage/garage.toml \
  -v /var/lib/garage/meta:/var/lib/garage/meta \
  -v /var/lib/garage/data:/var/lib/garage/data \
  lxpz/garage_amd64:v0.3.0

It should be restart automatically at each reboot. Please note that we use host networking as otherwise Docker containers can not communicate with IPv6.

Upgrading between Garage versions should be supported transparently, but please check the relase notes before doing so! To upgrade, simply stop and remove this container and start again the command with a new version of garage.

Controling the daemon

The garage binary has two purposes:

  • it acts as a daemon when launched with garage server ...
  • it acts as a control tool for the daemon when launched with any other command

In this section, we will see how to use the garage binary as a control tool for the daemon we just started. You first need to get a shell having access to this binary. For instance, enter the Docker container with:

sudo docker exec -ti garaged bash

You will now have a shell where the Garage binary is available as /garage/garage

You can also install the binary on your machine to remotely control the cluster.

Talk to the daemon and create an alias

garage requires 4 options to talk with the daemon:

--ca-cert <ca-cert>            
--client-cert <client-cert>    
--client-key <client-key>      
-h, --rpc-host <rpc-host>

The 3 first ones are certificates and keys needed by TLS, the last one is simply the address of garage's RPC endpoint.

If you are invoking garage from a server node directly, you do not need to set --rpc-host as the default value 127.0.0.1:3901 will allow it to contact Garage correctly.

To avoid typing the 3 first options each time we want to run a command, you can use the following alias:

alias garagectl='/garage/garage \
  --ca-cert /etc/garage/pki/garage-ca.crt \
  --client-cert /etc/garage/pki/garage.crt \
  --client-key /etc/garage/pki/garage.key'

You can now use all of the commands presented in the quick start guide, simply replace occurences of garage by garagectl.

Test the alias

You can test your alias by running a simple command such as:

garagectl status

You should get something like that as result:

Healthy nodes:
2a638ed6c775b69a…	37f0ba978d27	[::ffff:172.20.0.101]:3901	UNCONFIGURED/REMOVED
68143d720f20c89d…	9795a2f7abb5	[::ffff:172.20.0.103]:3901	UNCONFIGURED/REMOVED
8781c50c410a41b3…	758338dde686	[::ffff:172.20.0.102]:3901	UNCONFIGURED/REMOVED

Configuring a cluster

We will now inform garage of the disk space available on each node of the cluster as well as the zone (e.g. datacenter) in which each machine is located.

For our example, we will suppose we have the following infrastructure (Capacity, Identifier and Datacenter are specific values to garage described in the following):

Location Name Disk Space Capacity Identifier Zone
Paris Mercury 1 To 2 8781c5 par1
Paris Venus 2 To 4 2a638e par1
London Earth 2 To 4 68143d lon1
Brussels Mars 1.5 To 3 212f75 bru1

Node identifiers

After its first launch, garage generates a random and unique identifier for each nodes, such as:

8781c50c410a41b363167e9d49cc468b6b9e4449b6577b64f15a249a149bdcbc

Often a shorter form can be used, containing only the beginning of the identifier, like 8781c5, which identifies the server "Mercury" located in "Paris" according to our previous table.

The most simple way to match an identifier to a node is to run:

garagectl status

It will display the IP address associated with each node; from the IP address you will be able to recognize the node.

Zones

Zones are simply a user-chosen identifier that identify a group of server that are grouped together logically. It is up to the system administrator deploying garage to identify what does "grouped together" means.

In most cases, a zone will correspond to a geographical location (i.e. a datacenter). Behind the scene, Garage will use zone definition to try to store the same data on different zones, in order to provide high availability despite failure of a zone.

Capacity

Garage reasons on an arbitrary metric about disk storage that is named the capacity of a node. The capacity configured in Garage must be proportional to the disk space dedicated to the node. Additionaly, the capacity values used in Garage should be as small as possible, with 1 ideally representing the size of your smallest server.

Here we chose that 1 unit of capacity = 0.5 To, so that we can express servers of size 1 To and 2 To, as wel as the intermediate size 1.5 To.

Note that the amount of data stored by Garage on each server may not be strictly proportional to its capacity value, as Garage will priorize having 3 copies of data in different zones, even if this means that capacities will not be strictly respected. For example in our above examples, nodes Earth and Mars will always store a copy of everything each, and the third copy will have 66% chance of being stored by Venus and 33% chance of being stored by Mercury.

Injecting the topology

Given the information above, we will configure our cluster as follow:

garagectl node configure -z par1 -c 2 -t mercury 8781c5
garagectl node configure -z par1 -c 4 -t venus 2a638e
garagectl node configure -z lon1 -c 4 -t earth 68143d
garagectl node configure -z bru1 -c 3 -t mars 212f75