Global tags
cluster=<name>-
The cluster name. If metrics from multiple clusters are being collected, this tag helps identify where they belong to.
node=<node>-
The name of the node reporting the metric.
This is part of the Metrics for troubleshooting Keycloak deployment guide.
Metrics need to be enabled for Keycloak. Follow the Enabling Keycloak Metrics guide for more details.
A monitoring system collecting the metrics.
Deploying multiple Keycloak nodes allows the load to be distributed amongst them, but this requires communication between the nodes. This section describes metrics that are useful for monitoring the communication between Keycloak in order to identify possible faults.
| This is relevant only for single site deployments. When multiple sites are used, as described in Multi-site deployments, Keycloak nodes are not clustered together and therefore there is no communication between them directly. |
Global tags
cluster=<name>The cluster name. If metrics from multiple clusters are being collected, this tag helps identify where they belong to.
node=<node>The name of the node reporting the metric.
The following metrics expose the response time for the remote requests. The response time is measured between two nodes and includes the processing time. All requests are measured by these metrics, and the response time should remain stable through the cluster lifecycle.
| In a healthy cluster, the response time will remain stable. An increase in response time may indicate a degraded cluster or a node under heavy load. |
Tags
node=<node>It identifies the sender node.
target_node=<node>It identifies the receiver node.
| Metric | Description |
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The number of synchronous requests to a receiver node. |
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The total duration of synchronous request to a receiver node |
| When histogram is enabled, the percentile buckets are available. Those are useful to create heat maps but, collecting and exposing the percentile buckets may have a negative impact on the deployment performance. |
All the bytes received and sent by the Keycloak are collected by these metrics. Also, all the internal messages, as heartbeats, are counted too. They allow computing the bandwidth currently used by each node.
| The metric name depends on the JGroups transport protocol in use. |
| Metric | Protocol | Description |
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The total number of bytes received by a node. |
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The total number of bytes sent by a node. |
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Monitoring the thread pool size is a good indicator that a node is under a heavy load. All requests received are added to the thread pool for processing and, when it is full, the request is discarded. A retransmission mechanism ensures a reliable communication with an increase of resource usage.
In a healthy cluster, the thread pool should never be closer to its maximum size (by default, 200 threads).
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| Thread pool metrics are not available with virtual threads. Virtual threads are enabled by default when running with OpenJDK 21. |
| The metric name depends on the JGroups transport protocol in use. The default transport protocol is TCP. |
| Metric | Protocol | Description |
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Current number of threads in the thread pool. |
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The largest number of threads that have ever simultaneously been in the pool. |
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Flow control takes care of adjusting the rate of a message sender to the rate of the slowest receiver over time. This is implemented through a credit-based system, where each sender decrements its credits when sending. The sender blocks when the credits fall below 0, and only resumes sending messages when it receives a replenishment message from the receivers.
The metrics below show the number of blocked messages and the average blocking time. When a value is different from zero, it may signal that a receiver is overloaded and may degrade the cluster performance.
Each node has two independent flow control protocols, UFC for unicast messages and MFC for multicast messages.
| A healthy cluster shows a value of zero for all metrics. |
| Metric | Description |
|---|---|
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The number of times flow control blocks the sender for unicast messages. |
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Average time blocked (in ms) in flow control when trying to send an unicast message. |
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The number of times flow control blocks the sender for multicast messages. |
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Average time blocked (in ms) in flow control when trying to send a multicast message. |
JGroups provides reliable delivery of messages. When a message is dropped on the network, or the receiver cannot handle the message, a retransmission is required. Retransmissions increase resource usage, and it is usually a signal of an overload system.
Random Early Drop (RED) monitors the sender queues. When the queues are almost full, the message is dropped, and a retransmission must happen. It prevents threads from being blocked by a full sender queue.
| A healthy cluster shows a value of zero for all metrics. |
| Metric | Description |
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The number of retransmitted messages. |
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The total number of dropped messages by the sender. |
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Percentage of all messages that were dropped by the sender. |
The cluster size metric reports the number of nodes present in the cluster. If it differs, it may signal that a node is joining, shutdown or, in the worst case, a network partition is happening.
| A healthy cluster shows the same value in all nodes. |
| Metric | Description |
|---|---|
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The number of nodes in the cluster. |
Network partitions in a cluster can happen due to various reasons. This metrics does not help predict network splits but signals that it happened, and the cluster has been merged.
| A healthy cluster shows a value of zero for this metric. |
| Metric | Description |
|---|---|
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The amount of time a network split was detected and healed. |
Return back to the Metrics for troubleshooting Keycloak deployment or proceed to Embedded Infinispan metrics for single site deployments.