Configuration file format

12 min

Here is an example garage.toml configuration file that illustrates all of the possible options:

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

block_size = 1048576

replication_mode = "3"

compression_level = 1

rpc_secret = "4425f5c26c5e11581d3223904324dcb5b5d5dfb14e5e7f35e38c595424f5f1e6"
rpc_bind_addr = "[::]:3901"
rpc_public_addr = "[fc00:1::1]:3901"

bootstrap_peers = [
    "563e1ac825ee3323aa441e72c26d1030d6d4414aeb3dd25287c531e7fc2bc95d@[fc00:1::1]:3901",
    "86f0f26ae4afbd59aaf9cfb059eefac844951efd5b8caeec0d53f4ed6c85f332[fc00:1::2]:3901",
    "681456ab91350f92242e80a531a3ec9392cb7c974f72640112f90a600d7921a4@[fc00:B::1]:3901",
    "212fd62eeaca72c122b45a7f4fa0f55e012aa5e24ac384a72a3016413fa724ff@[fc00:F::1]:3901",
]

consul_host = "consul.service"
consul_service_name = "garage-daemon"

kubernetes_namespace = "garage"
kubernetes_service_name = "garage-daemon"
kubernetes_skip_crd = false

sled_cache_capacity = 134217728
sled_flush_every_ms = 2000

[s3_api]
api_bind_addr = "[::]:3900"
s3_region = "garage"
root_domain = ".s3.garage"

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

[admin]
api_bind_addr = "0.0.0.0:3903"
trace_sink = "http://localhost:4317"

The following gives details about each available configuration option.

Available configuration options

metadata_dir

The directory in which Garage will store its metadata. This contains the node identifier, the network configuration and the peer list, the list of buckets and keys as well as the index of all objects, object version and object blocks.

Store this folder on a fast SSD drive if possible to maximize Garage's performance.

data_dir

The directory in which Garage will store the data blocks of objects. This folder can be placed on an HDD. The space available for data_dir should be counted to determine a node's capacity when adding it to the cluster layout.

block_size

Garage splits stored objects in consecutive chunks of size block_size (except the last one which might be smaller). The default size is 1MB and should work in most cases. We recommend increasing it to e.g. 10MB if you are using Garage to store large files and have fast network connections between all nodes (e.g. 1gbps).

If you are interested in tuning this, feel free to do so (and remember to report your findings to us!). When this value is changed for a running Garage installation, only files newly uploaded will be affected. Previously uploaded files will remain available. This however means that chunks from existing files will not be deduplicated with chunks from newly uploaded files, meaning you might use more storage space that is optimally possible.

replication_mode

Garage supports the following replication modes:

  • none or 1: data stored on Garage is stored on a single node. There is no redundancy, and data will be unavailable as soon as one node fails or its network is disconnected. Do not use this for anything else than test deployments.

  • 2: data stored on Garage will be stored on two different nodes, if possible in different zones. Garage tolerates one node failure, or several nodes failing but all in a single zone (in a deployment with at least two zones), before losing data. Data remains available in read-only mode when one node is down, but write operations will fail.

    • 2-dangerous: a variant of mode 2, where written objects are written to the second replica asynchronously. This means that Garage will return 200 OK to a PutObject request before the second copy is fully written (or even before it even starts being written). This means that data can more easily be lost if the node crashes before a second copy can be completed. This also means that written objects might not be visible immediately in read operations. In other words, this mode severely breaks the consistency and durability guarantees of standard Garage cluster operation. Benefits of this mode: you can still write to your cluster when one node is unavailable.
  • 3: data stored on Garage will be stored on three different nodes, if possible each in a different zones. Garage tolerates two node failure, or several node failures but in no more than two zones (in a deployment with at least three zones), before losing data. As long as only a single node fails, or node failures are only in a single zone, reading and writing data to Garage can continue normally.

    • 3-degraded: a variant of replication mode 3, that lowers the read quorum to 1, to allow you to read data from your cluster when several nodes (or nodes in several zones) are unavailable. In this mode, Garage does not provide read-after-write consistency anymore. The write quorum is still 2, ensuring that data successfully written to Garage is stored on at least two nodes.

    • 3-dangerous: a variant of replication mode 3 that lowers both the read and write quorums to 1, to allow you to both read and write to your cluster when several nodes (or nodes in several zones) are unavailable. It is the least consistent mode of operation proposed by Garage, and also one that should probably never be used.

Note that in modes 2 and 3, if at least the same number of zones are available, an arbitrary number of failures in any given zone is tolerated as copies of data will be spread over several zones.

Make sure replication_mode is the same in the configuration files of all nodes. Never run a Garage cluster where that is not the case.

The quorums associated with each replication mode are described below:

replication_modeNumber of replicasWrite quorumRead quorumRead-after-write consistency?
none or 1111yes
2221yes
2-dangerous211NO
3322yes
3-degraded321NO
3-dangerous311NO

Changing the replication_mode between modes with the same number of replicas (e.g. from 3 to 3-degraded, or from 2-dangerous to 2), can be done easily by just changing the replication_mode parameter in your config files and restarting all your Garage nodes.

It is also technically possible to change the replication mode to a mode with a different numbers of replicas, although it's a dangerous operation that is not officially supported. This requires you to delete the existing cluster layout and create a new layout from scratch, meaning that a full rebalancing of your cluster's data will be needed. To do it, shut down your cluster entirely, delete the custer_layout files in the meta directories of all your nodes, update all your configuration files with the new replication_mode parameter, restart your cluster, and then create a new layout with all the nodes you want to keep. Rebalancing data will take some time, and data might temporarily appear unavailable to your users. It is recommended to shut down public access to the cluster while rebalancing is in progress. In theory, no data should be lost as rebalancing is a routine operation for Garage, although we cannot guarantee you that everything will go right in such an extreme scenario.

compression_level

Zstd compression level to use for storing blocks.

Values between 1 (faster compression) and 19 (smaller file) are standard compression levels for zstd. From 20 to 22, compression levels are referred as "ultra" and must be used with extra care as it will use lot of memory. A value of 0 will let zstd choose a default value (currently 3). Finally, zstd has also compression designed to be faster than default compression levels, they range from -1 (smaller file) to -99 (faster compression).

If you do not specify a compression_level entry, Garage will set it to 1 for you. With this parameters, zstd consumes low amount of cpu and should work faster than line speed in most situations, while saving some space and intra-cluster bandwidth.

If you want to totally deactivate zstd in Garage, you can pass the special value 'none'. No zstd related code will be called, your chunks will be stored on disk without any processing.

Compression is done synchronously, setting a value too high will add latency to write queries.

This value can be different between nodes, compression is done by the node which receive the API call.

rpc_secret

Garage uses a secret key that is shared between all nodes of the cluster in order to identify these nodes and allow them to communicate together. This key should be specified here in the form of a 32-byte hex-encoded random string. Such a string can be generated with a command such as openssl rand -hex 32.

rpc_bind_addr

The address and port on which to bind for inter-cluster communcations (reffered to as RPC for remote procedure calls). The port specified here should be the same one that other nodes will used to contact the node, even in the case of a NAT: the NAT should be configured to forward the external port number to the same internal port nubmer. This means that if you have several nodes running behind a NAT, they should each use a different RPC port number.

rpc_public_addr

The address and port that other nodes need to use to contact this node for RPC calls. This parameter is optional but recommended. In case you have a NAT that binds the RPC port to a port that is different on your public IP, this field might help making it work.

bootstrap_peers

A list of peer identifiers on which to contact other Garage peers of this cluster. These peer identifiers have the following syntax:

<node public key>@<node public IP or hostname>:<port>

In the case where rpc_public_addr is correctly specified in the configuration file, the full identifier of a node including IP and port can be obtained by running garage node id and then included directly in the bootstrap_peers list of other nodes. Otherwise, only the node's public key will be returned by garage node id and you will have to add the IP yourself.

consul_host and consul_service_name

Garage supports discovering other nodes of the cluster using Consul. For this to work correctly, nodes need to know their IP address by which they can be reached by other nodes of the cluster, which should be set in rpc_public_addr.

The consul_host parameter should be set to the hostname of the Consul server, and consul_service_name should be set to the service name under which Garage's RPC ports are announced.

Garage does not yet support talking to Consul over TLS.

kubernetes_namespace, kubernetes_service_name and kubernetes_skip_crd

Garage supports discovering other nodes of the cluster using kubernetes custom resources. For this to work kubernetes_namespace and kubernetes_service_name need to be configured.

kubernetes_namespace sets the namespace in which the custom resources are configured. kubernetes_service_name is added as a label to these resources to filter them, to allow for multiple deployments in a single namespace.

kubernetes_skip_crd can be set to true to disable the automatic creation and patching of the garagenodes.deuxfleurs.fr CRD. You will need to create the CRD manually.

sled_cache_capacity

This parameter can be used to tune the capacity of the cache used by sled, the database Garage uses internally to store metadata. Tune this to fit the RAM you wish to make available to your Garage instance. This value has a conservative default (128MB) so that Garage doesn't use too much RAM by default, but feel free to increase this for higher performance.

sled_flush_every_ms

This parameters can be used to tune the flushing interval of sled. Increase this if sled is thrashing your SSD, at the risk of losing more data in case of a power outage (though this should not matter much as data is replicated on other nodes). The default value, 2000ms, should be appropriate for most use cases.

The [s3_api] section

api_bind_addr

The IP and port on which to bind for accepting S3 API calls. This endpoint does not suport TLS: a reverse proxy should be used to provide it.

s3_region

Garage will accept S3 API calls that are targetted to the S3 region defined here. API calls targetted to other regions will fail with a AuthorizationHeaderMalformed error message that redirects the client to the correct region.

root_domain

The optionnal suffix to access bucket using vhost-style in addition to path-style request. Note path-style requests are always enabled, whether or not vhost-style is configured. Configuring vhost-style S3 required a wildcard DNS entry, and possibly a wildcard TLS certificate, but might be required by softwares not supporting path-style requests.

If root_domain is s3.garage.eu, a bucket called my-bucket can be interacted with using the hostname my-bucket.s3.garage.eu.

The [s3_web] section

Garage allows to publish content of buckets as websites. This section configures the behaviour of this module.

bind_addr

The IP and port on which to bind for accepting HTTP requests to buckets configured for website access. This endpoint does not suport TLS: a reverse proxy should be used to provide it.

root_domain

The optionnal suffix appended to bucket names for the corresponding HTTP Host.

For instance, if root_domain is web.garage.eu, a bucket called deuxfleurs.fr will be accessible either with hostname deuxfleurs.fr.web.garage.eu or with hostname deuxfleurs.fr.

The [admin] section

Garage has a few administration capabilities, in particular to allow remote monitoring. These features are detailed below.

api_bind_addr

If specified, Garage will bind an HTTP server to this port and address, on which it will listen to requests for administration features. Currently, this endpoint only exposes Garage metrics in the Prometheus format at /metrics. This endpoint is not authenticated. In the future, bucket and access key management might be possible by REST calls to this endpoint.

trace_sink

Optionnally, the address of an Opentelemetry collector. If specified, Garage will send traces in the Opentelemetry format to this endpoint. These trace allow to inspect Garage's operation when it handles S3 API requests.