Add best practices and doc of monitoring (fix #419)

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Alex 3 weeks ago
parent bcc9772470
commit a7af0c8af9
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  1. 305
      doc/book/cookbook/monitoring.md
  2. 46
      doc/book/cookbook/real-world.md
  3. 2
      doc/book/cookbook/recovering.md
  4. 2
      doc/book/cookbook/upgrading.md
  5. 3
      doc/book/quick-start/_index.md
  6. 1053
      script/telemetry/grafana-garage-dashboard-prometheus.json

@ -0,0 +1,305 @@
+++
title = "Monitoring Garage"
weight = 40
+++
Garage exposes some internal metrics in the Prometheus data format.
This page explains how to exploit these metrics.
## Setting up monitoring
### Enabling the Admin API endpoint
If you have not already enabled the [administration API endpoint](@/documentation/reference-manual/admin-api.md), do so by adding the following lines to your configuration file:
```toml
[admin]
api_bind_addr = "0.0.0.0:3903"
```
This will allow anyone to scrape Prometheus metrics by fetching
`http://localhost:3093/metrics`. If you want to restrict access
to the exported metrics, set the `metrics_token` configuration value
to a bearer token to be used when fetching the metrics endpoint.
### Setting up Prometheus and Grafana
Add a scrape config to your Prometheus daemon to scrape metrics from
all of your nodes:
```yaml
scrape_configs:
- job_name: 'garage'
static_configs:
- targets:
- 'node1.mycluster:3903'
- 'node2.mycluster:3903'
- 'node3.mycluster:3903'
```
If you have set a metrics token in your Garage configuration file,
add the following lines in your Prometheus scrape config:
```yaml
authorization:
type: Bearer
credentials: 'your metrics token'
```
To visualize the scraped data in Grafana,
you can either import our [Grafana dashboard for Garage](https://git.deuxfleurs.fr/Deuxfleurs/garage/raw/branch/main/script/telemetry/grafana-garage-dashboard-prometheus.json)
or make your own.
We detail below the list of exposed metrics and their meaning.
## List of exported metrics
### API endpoints
#### `api_admin_request_counter` (counter)
Counts the number of requests to a given endpoint of the administration API. Example:
```
api_admin_request_counter{api_endpoint="Metrics"} 127041
```
#### `api_admin_request_duration` (histogram)
Evaluates the duration of API calls to the various administration API endpoint. Example:
```
api_admin_request_duration_bucket{api_endpoint="Metrics",le="0.5"} 127041
api_admin_request_duration_sum{api_endpoint="Metrics"} 605.250344830999
api_admin_request_duration_count{api_endpoint="Metrics"} 127041
```
#### `api_s3_request_counter` (counter)
Counts the number of requests to a given endpoint of the S3 API. Example:
```
api_s3_request_counter{api_endpoint="CreateMultipartUpload"} 1
```
#### `api_s3_error_counter` (counter)
Counts the number of requests to a given endpoint of the S3 API that returned an error. Example:
```
api_s3_error_counter{api_endpoint="GetObject",status_code="404"} 39
```
#### `api_s3_request_duration` (histogram)
Evaluates the duration of API calls to the various S3 API endpoints. Example:
```
api_s3_request_duration_bucket{api_endpoint="CreateMultipartUpload",le="0.5"} 1
api_s3_request_duration_sum{api_endpoint="CreateMultipartUpload"} 0.046340762
api_s3_request_duration_count{api_endpoint="CreateMultipartUpload"} 1
```
#### `api_k2v_request_counter` (counter), `api_k2v_error_counter` (counter), `api_k2v_error_duration` (histogram)
Same as for S3, for the K2V API.
### Web endpoint
#### `web_request_counter` (counter)
Number of requests to the web endpoint
```
web_request_counter{method="GET"} 80
```
#### `web_request_duration` (histogram)
Duration of requests to the web endpoint
```
web_request_duration_bucket{method="GET",le="0.5"} 80
web_request_duration_sum{method="GET"} 1.0528433229999998
web_request_duration_count{method="GET"} 80
```
#### `web_error_counter` (counter)
Number of requests to the web endpoint resulting in errors
```
web_error_counter{method="GET",status_code="404 Not Found"} 64
```
### Data block manager
#### `block_bytes_read`, `block_bytes_written` (counter)
Number of bytes read/written to/from disk in the data storage directory.
```
block_bytes_read 120586322022
block_bytes_written 3386618077
```
#### `block_read_duration`, `block_write_duration` (histograms)
Evaluates the duration of the reading/writing of individual data blocks in the data storage directory.
```
block_read_duration_bucket{le="0.5"} 169229
block_read_duration_sum 2761.6902550310056
block_read_duration_count 169240
block_write_duration_bucket{le="0.5"} 3559
block_write_duration_sum 195.59170078500006
block_write_duration_count 3571
```
#### `block_delete_counter` (counter)
Counts the number of data blocks that have been deleted from storage.
```
block_delete_counter 122
```
#### `block_resync_counter` (counter), `block_resync_duration` (histogram)
Counts the number of resync operations the node has executed, and evaluates their duration.
```
block_resync_counter 308897
block_resync_duration_bucket{le="0.5"} 308892
block_resync_duration_sum 139.64204196100016
block_resync_duration_count 308897
```
#### `block_resync_queue_length` (gauge)
The number of block hashes currently queued for a resync.
This is normal to be nonzero for long periods of time.
```
block_resync_queue_length 0
```
#### `block_resync_errored_blocks` (gauge)
The number of block hashes that we were unable to resync last time we tried.
**THIS SHOULD BE ZERO, OR FALL BACK TO ZERO RAPIDLY, IN A HEALTHY CLUSTER.**
```
block_resync_errored_blocks 0
```
### RPC (remote procedure calls) between nodes
#### `rpc_netapp_request_counter` (counter)
Number of RPC requests emitted
```
rpc_request_counter{from="<this node>",rpc_endpoint="garage_block/manager.rs/Rpc",to="<remote node>"} 176
```
#### `rpc_netapp_error_counter` (counter)
Number of communication errors (errors in the Netapp library)
```
rpc_netapp_error_counter{from="<this node>",rpc_endpoint="garage_block/manager.rs/Rpc",to="<remote node>"} 354
```
#### `rpc_timeout_counter` (counter)
Number of RPC timeouts
```
rpc_timeout_counter{from="<this node>",rpc_endpoint="garage_rpc/membership.rs/SystemRpc",to="<remote node>"} 1
```
#### `rpc_duration` (histogram)
The duration of internal RPC calls between Garage nodes.
```
rpc_duration_bucket{from="<this node>",rpc_endpoint="garage_block/manager.rs/Rpc",to="<remote node>",le="0.5"} 166
rpc_duration_sum{from="<this node>",rpc_endpoint="garage_block/manager.rs/Rpc",to="<remote node>"} 35.172253716
rpc_duration_count{from="<this node>",rpc_endpoint="garage_block/manager.rs/Rpc",to="<remote node>"} 174
```
### Metadata table manager
#### `table_gc_todo_queue_length` (gauge)
Table garbage collector TODO queue length
```
table_gc_todo_queue_length{table_name="block_ref"} 0
```
#### `table_get_request_counter` (counter), `table_get_request_duration` (histogram)
Number of get/get_range requests internally made on each table, and their duration.
```
table_get_request_counter{table_name="bucket_alias"} 315
table_get_request_duration_bucket{table_name="bucket_alias",le="0.5"} 315
table_get_request_duration_sum{table_name="bucket_alias"} 0.048509778000000024
table_get_request_duration_count{table_name="bucket_alias"} 315
```
#### `table_put_request_counter` (counter), `table_put_request_duration` (histogram)
Number of insert/insert_many requests internally made on this table, and their duration
```
table_put_request_counter{table_name="block_ref"} 677
table_put_request_duration_bucket{table_name="block_ref",le="0.5"} 677
table_put_request_duration_sum{table_name="block_ref"} 61.617528636
table_put_request_duration_count{table_name="block_ref"} 677
```
#### `table_internal_delete_counter` (counter)
Number of value deletions in the tree (due to GC or repartitioning)
```
table_internal_delete_counter{table_name="block_ref"} 2296
```
#### `table_internal_update_counter` (counter)
Number of value updates where the value actually changes (includes creation of new key and update of existing key)
```
table_internal_update_counter{table_name="block_ref"} 5996
```
#### `table_merkle_updater_todo_queue_length` (gauge)
Merkle tree updater TODO queue length (should fall to zero rapidly)
```
table_merkle_updater_todo_queue_length{table_name="block_ref"} 0
```
#### `table_sync_items_received`, `table_sync_items_sent` (counters)
Number of data items sent to/recieved from other nodes during resync procedures
```
table_sync_items_received{from="<remote node>",table_name="bucket_v2"} 3
table_sync_items_sent{table_name="block_ref",to="<remote node>"} 2
```

@ -11,8 +11,9 @@ We recommend first following the [quick start guide](@/documentation/quick-start
to get familiar with Garage's command line and usage patterns.
## Preparing your environment
## Prerequisites
### Prerequisites
To run a real-world deployment, make sure the following conditions are met:
@ -21,10 +22,6 @@ To run a real-world deployment, make sure the following conditions are met:
- Each machine has a public IP address which is reachable by other machines.
Running behind a NAT is likely to be possible but hasn't been tested for the latest version (TODO).
- 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 significantly reduce Garage's response times.
- This guide will assume you are using Docker containers to deploy Garage on each node.
Garage can also be run independently, for instance as a [Systemd service](@/documentation/cookbook/systemd.md).
You can also use an orchestrator such as Nomad or Kubernetes to automatically manage
@ -49,6 +46,42 @@ available in the different locations of your cluster is roughly the same.
For instance, here, the Mercury node could be moved to Brussels; this would allow the cluster
to store 2 TB of data in total.
### Best practices
- If you have fast dedicated networking between all your nodes, and are planing to store
very large files, bump the `block_size` configuration parameter to 10 MB
(`block_size = 10485760`).
- Garage stores its files in two locations: it uses a metadata directory to store frequently-accessed
small metadata items, and a data directory to store data blocks of uploaded objects.
Ideally, the metadata directory would be stored on an SSD (smaller but faster),
and the data directory would be stored on an HDD (larger but slower).
- For the data directory, Garage already does checksumming and integrity verification,
so there is no need to use a filesystem such as BTRFS or ZFS that does it.
We recommend using XFS for the data partition, as it has the best performance.
Ext4 is not recommended as it has more strict limitations on the number of inodes,
which might cause issues with Garage when large numbers of objects are stored.
- If you only have an HDD and no SSD, it's fine to put your metadata alongside the data
on the same drive. Having lots of RAM for your kernel to cache the metadata will
help a lot with performance. Make sure to use the LMDB database engine,
instead of Sled, which suffers from quite bad performance degradation on HDDs.
Sled is still the default for legacy reasons, but is not recommended anymore.
- For the metadata storage, Garage does not do checksumming and integrity
verification on its own. If you are afraid of bitrot/data corruption,
put your metadata directory on a BTRFS partition. Otherwise, just use regular
EXT4 or XFS.
- Having a single server with several storage drives is currently not very well
supported in Garage ([#218](https://git.deuxfleurs.fr/Deuxfleurs/garage/issues/218)).
For an easy setup, just put all your drives in a RAID0 or a ZFS RAIDZ array.
If you're adventurous, you can try to format each of your disk as
a separate XFS partition, and then run one `garage` daemon per disk drive,
or use something like [`mergerfs`](https://github.com/trapexit/mergerfs) to merge
all your disks in a single union filesystem that spreads load over them.
## Get a Docker image
Our docker image is currently named `dxflrs/garage` and is stored on the [Docker Hub](https://hub.docker.com/r/dxflrs/garage/tags?page=1&ordering=last_updated).
@ -81,6 +114,7 @@ A valid `/etc/garage/garage.toml` for our cluster would look as follows:
```toml
metadata_dir = "/var/lib/garage/meta"
data_dir = "/var/lib/garage/data"
db_engine = "lmdb"
replication_mode = "3"
@ -90,8 +124,6 @@ rpc_bind_addr = "[::]:3901"
rpc_public_addr = "<this node's public IP>:3901"
rpc_secret = "<RPC secret>"
bootstrap_peers = []
[s3_api]
s3_region = "garage"
api_bind_addr = "[::]:3900"

@ -1,6 +1,6 @@
+++
title = "Recovering from failures"
weight = 35
weight = 50
+++
Garage is meant to work on old, second-hand hardware.

@ -1,6 +1,6 @@
+++
title = "Upgrading Garage"
weight = 40
weight = 60
+++
Garage is a stateful clustered application, where all nodes are communicating together and share data structures.

@ -54,6 +54,7 @@ to generate unique and private secrets for security reasons:
cat > garage.toml <<EOF
metadata_dir = "/tmp/meta"
data_dir = "/tmp/data"
db_engine = "lmdb"
replication_mode = "none"
@ -61,8 +62,6 @@ rpc_bind_addr = "[::]:3901"
rpc_public_addr = "127.0.0.1:3901"
rpc_secret = "$(openssl rand -hex 32)"
bootstrap_peers = []
[s3_api]
s3_region = "garage"
api_bind_addr = "[::]:3900"

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