Configure local metrics and logs for Azure API Management self-hosted gateway
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This article provides details for configuring local metrics and logs for the self-hosted gateway deployed on a Kubernetes cluster. For configuring cloud metrics and logs, see this article.
Metrics
The self-hosted gateway supports StatsD, which has become a unifying protocol for metrics collection and aggregation. This section walks through the steps for deploying StatsD to Kubernetes, configuring the gateway to emit metrics via StatsD, and using Prometheus to monitor the metrics.
Deploy StatsD and Prometheus to the cluster
The following sample YAML configuration deploys StatsD and Prometheus to the Kubernetes cluster where a self-hosted gateway is deployed. It also creates a Service for each. The self-hosted gateway then publishes metrics to the StatsD Service. We'll access the Prometheus dashboard via its Service.
Note
The following example pulls public container images from Docker Hub. We recommend that you set up a pull secret to authenticate using a Docker Hub account instead of making an anonymous pull request. To improve reliability when working with public content, import and manage the images in a private Azure container registry. Learn more about working with public images.
apiVersion: v1
kind: ConfigMap
metadata:
name: sputnik-metrics-config
data:
statsd.yaml: ""
prometheus.yaml: |
global:
scrape_interval: 3s
evaluation_interval: 3s
scrape_configs:
- job_name: 'prometheus'
static_configs:
- targets: ['localhost:9090']
- job_name: 'test_metrics'
static_configs:
- targets: ['localhost:9102']
---
apiVersion: apps/v1
kind: Deployment
metadata:
name: sputnik-metrics
spec:
replicas: 1
selector:
matchLabels:
app: sputnik-metrics
template:
metadata:
labels:
app: sputnik-metrics
spec:
containers:
- name: sputnik-metrics-statsd
image: prom/statsd-exporter
ports:
- name: tcp
containerPort: 9102
- name: udp
containerPort: 8125
protocol: UDP
args:
- --statsd.mapping-config=/tmp/statsd.yaml
- --statsd.listen-udp=:8125
- --web.listen-address=:9102
volumeMounts:
- mountPath: /tmp
name: sputnik-metrics-config-files
- name: sputnik-metrics-prometheus
image: prom/prometheus
ports:
- name: tcp
containerPort: 9090
args:
- --config.file=/tmp/prometheus.yaml
volumeMounts:
- mountPath: /tmp
name: sputnik-metrics-config-files
volumes:
- name: sputnik-metrics-config-files
configMap:
name: sputnik-metrics-config
---
apiVersion: v1
kind: Service
metadata:
name: sputnik-metrics-statsd
spec:
type: NodePort
ports:
- name: udp
port: 8125
targetPort: 8125
protocol: UDP
selector:
app: sputnik-metrics
---
apiVersion: v1
kind: Service
metadata:
name: sputnik-metrics-prometheus
spec:
type: LoadBalancer
ports:
- name: http
port: 9090
targetPort: 9090
selector:
app: sputnik-metrics
Save the configurations to a file named metrics.yaml. Use the following command to deploy everything to the cluster:
kubectl apply -f metrics.yaml
Once the deployment finishes, run the following command to check the Pods are running. Your pod name will be different.
kubectl get pods
NAME READY STATUS RESTARTS AGE
sputnik-metrics-f6d97548f-4xnb7 2/2 Running 0 1m
Run the below command to check the services are running. Take a note of the CLUSTER-IP and PORT of the StatsD Service, which we use later. You can visit the Prometheus dashboard using its EXTERNAL-IP and PORT.
kubectl get services
NAME TYPE CLUSTER-IP EXTERNAL-IP PORT(S) AGE
sputnik-metrics-prometheus LoadBalancer 10.0.252.72 13.89.141.90 9090:32663/TCP 18h
sputnik-metrics-statsd NodePort 10.0.41.179 <none> 8125:32733/UDP 18h
Configure the self-hosted gateway to emit metrics
Now that both StatsD and Prometheus are deployed, we can update the configurations of the self-hosted gateway to start emitting metrics through StatsD. The feature can be enabled or disabled using the telemetry.metrics.local key in the ConfigMap of the self-hosted gateway Deployment with additional options. The following are the available options:
| Field | Default | Description |
|---|---|---|
| telemetry.metrics.local | none |
Enables logging through StatsD. Value can be none, statsd. |
| telemetry.metrics.local.statsd.endpoint | n/a | Specifies StatsD endpoint. |
| telemetry.metrics.local.statsd.sampling | n/a | Specifies metrics sampling rate. Value can be between 0 and 1. Example: 0.5 |
| telemetry.metrics.local.statsd.tag-format | n/a | StatsD exporter tagging format. Value can be none, librato, dogStatsD, influxDB. |
Here's a sample configuration:
apiVersion: v1
kind: ConfigMap
metadata:
name: contoso-gateway-environment
data:
config.service.endpoint: "<self-hosted-gateway-management-endpoint>"
telemetry.metrics.local: "statsd"
telemetry.metrics.local.statsd.endpoint: "10.0.41.179:8125"
telemetry.metrics.local.statsd.sampling: "1"
telemetry.metrics.local.statsd.tag-format: "dogStatsD"
Update the YAML file of the self-hosted gateway deployment with the above configurations and apply the changes using the below command:
kubectl apply -f <file-name>.yaml
To pick up the latest configuration changes, restart the gateway deployment using the below command:
kubectl rollout restart deployment/<deployment-name>
View the metrics
Now we have everything deployed and configured, the self-hosted gateway should report metrics via StatsD. Prometheus then picks up the metrics from StatsD. Go to the Prometheus dashboard using the EXTERNAL-IP and PORT of the Prometheus Service.
Make some API calls through the self-hosted gateway, if everything is configured correctly, you should be able to view below metrics:
| Metric | Description |
|---|---|
| requests_total | Number of API requests in the period |
| request_duration_seconds | Number of milliseconds from the moment gateway received request until the moment response sent in full |
| request_backend_duration_seconds | Number of milliseconds spent on overall backend IO (connecting, sending, and receiving bytes) |
| request_client_duration_seconds | Number of milliseconds spent on overall client IO (connecting, sending, and receiving bytes) |
Logs
The self-hosted gateway outputs logs to stdout and stderr by default. You can easily view the logs using the following command:
kubectl logs <pod-name>
If your self-hosted gateway is deployed in Azure Kubernetes Service, you can enable Azure Monitor for containers to collect stdout and stderr from your workloads and view the logs in Log Analytics.
The self-hosted gateway also supports many protocols including localsyslog, rfc5424, and journal. The following table summarizes all the options supported.
| Field | Default | Description |
|---|---|---|
| telemetry.logs.std | text |
Enables logging to standard streams. Value can be none, text, json |
| telemetry.logs.local | auto |
Enables local logging. Value can be none, auto, localsyslog, rfc5424, journal, json |
| telemetry.logs.local.localsyslog.endpoint | n/a | Specifies local syslog endpoint. For details, see using local syslog logs. |
| telemetry.logs.local.localsyslog.facility | n/a | Specifies local syslog facility code. Example: 7 |
| telemetry.logs.local.rfc5424.endpoint | n/a | Specifies rfc5424 endpoint. |
| telemetry.logs.local.rfc5424.facility | n/a | Specifies facility code per rfc5424. Example: 7 |
| telemetry.logs.local.journal.endpoint | n/a | Specifies journal endpoint. |
| telemetry.logs.local.json.endpoint | 127.0.0.1:8888 | Specifies UDP endpoint that accepts JSON data: file path, IP:port, or hostname:port. |
Here's a sample configuration of local logging:
apiVersion: v1
kind: ConfigMap
metadata:
name: contoso-gateway-environment
data:
config.service.endpoint: "<self-hosted-gateway-management-endpoint>"
telemetry.logs.std: "text"
telemetry.logs.local.localsyslog.endpoint: "/dev/log"
telemetry.logs.local.localsyslog.facility: "7"
Using local JSON endpoint
Known limitations
- We only support up to 3072 bytes of request/response payload for local diagnostics. Anything above, may break JSON format due to chunking.
Using local syslog logs
Configuring gateway to stream logs
When using local syslog as a destination for logs, the runtime needs to allow streaming logs to the destination. For Kubernetes, a volume needs to be mounted which that matches the destination.
Given the following configuration:
apiVersion: v1
kind: ConfigMap
metadata:
name: contoso-gateway-environment
data:
config.service.endpoint: "<self-hosted-gateway-management-endpoint>"
telemetry.logs.local: localsyslog
telemetry.logs.local.localsyslog.endpoint: /dev/log
You can easily start streaming logs to that local syslog endpoint:
apiVersion: apps/v1
kind: Deployment
metadata:
name: contoso-deployment
labels:
app: contoso
spec:
replicas: 1
selector:
matchLabels:
app: contoso
template:
metadata:
labels:
app: contoso
spec:
containers:
name: azure-api-management-gateway
image: mcr.microsoft.com/azure-api-management/gateway:2.5.0
imagePullPolicy: IfNotPresent
envFrom:
- configMapRef:
name: contoso-gateway-environment
# ... redacted ...
+ volumeMounts:
+ - mountPath: /dev/log
+ name: logs
+ volumes:
+ - hostPath:
+ path: /dev/log
+ type: Socket
+ name: logs
Consuming local syslog logs on Azure Kubernetes Service (AKS)
When configuring to use local syslog on Azure Kubernetes Service, you can choose two ways to explore the logs:
- Use Syslog collection with Container Insights
- Connect & explore logs on the worker nodes
Consuming logs from worker nodes
You can easily consume them by getting access to the worker nodes:
- Create an SSH connection to the node (docs)
- Logs can be found under
host/var/log/syslog
For example, you can filter all syslogs to just the ones from the self-hosted gateway:
$ cat host/var/log/syslog | grep "apimuser"
May 15 05:54:20 aks-agentpool-43853532-vmss000000 apimuser[8]: Timestamp=2023-05-15T05:54:20.0445178Z, isRequestSuccess=True, totalTime=290, category=GatewayLogs, callerIpAddress=141.134.132.243, timeGenerated=2023-05-15T05:54:20.0445178Z, region=Repro, correlationId=b28565ec-73e0-41e6-9312-efcdd6841846, method=GET, url="http://20.126.242.200/echo/resource?param1\=sample", backendResponseCode=200, responseCode=200, responseSize=628, cache=none, backendTime=287, apiId=echo-api, operationId=retrieve-resource, apimSubscriptionId=master, clientProtocol=HTTP/1.1, backendProtocol=HTTP/1.1, apiRevision=1, backendMethod=GET, backendUrl="http://echoapi.cloudapp.net/api/resource?param1\=sample"
May 15 05:54:21 aks-agentpool-43853532-vmss000000 apimuser[8]: Timestamp=2023-05-15T05:54:21.1189171Z, isRequestSuccess=True, totalTime=150, category=GatewayLogs, callerIpAddress=141.134.132.243, timeGenerated=2023-05-15T05:54:21.1189171Z, region=Repro, correlationId=ab4d7464-acee-40ae-af95-a521cc57c759, method=GET, url="http://20.126.242.200/echo/resource?param1\=sample", backendResponseCode=200, responseCode=200, responseSize=628, cache=none, backendTime=148, apiId=echo-api, operationId=retrieve-resource, apimSubscriptionId=master, clientProtocol=HTTP/1.1, backendProtocol=HTTP/1.1, apiRevision=1, backendMethod=GET, backendUrl="http://echoapi.cloudapp.net/api/resource?param1\=sample"
Note
If you have changed the root with chroot, for example chroot /host, then the above path needs to reflect that change.
Next steps
- Learn about the observability capabilities of the Azure API Management gateways.
- Learn more about the Azure API Management self-hosted gateway.
- Learn about configuring and persisting logs in the cloud.