Monitoring Garage

5 min

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, do so by adding the following lines to your configuration file:

[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:

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:

    authorization:
      type: Bearer
      credentials: 'your metrics token'

To visualize the scraped data in Grafana, you can either import our Grafana dashboard for Garage or make your own. We detail below the list of exposed metrics and their meaning.

List of exported metrics

Metrics of the 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.

Metrics of the 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

Metrics of the 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. Persistent nonzero values indicate that some data is likely to be lost.

block_resync_errored_blocks 0

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, generally due to disconnected nodes)

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, should be close to zero in a healthy cluster.

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

Metrics of the 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
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