To use the java agent more natively, we propose the java agent injector to inject the agent sidecar into a pod.
When enabled in a pod's namespace, the injector injects the java agent container at pod creation time using a mutating webhook admission controller. By rendering the java agent to a shared volume, containers within the pod can use the java agent.
The following sections describe how to configure the agent, if you want to try it directly, please see Usage for more details.
The java agent injector is a component of the operator, so you need to follow Operator installation instrument to install the operator firstly.
We have two granularities here: namespace and pod.
| Resource | Label | Enabled value | Disabled value |
|---|---|---|---|
| Namespace | swck-injection | enabled | disabled |
| Pod | swck-java-agent-injected | "true" | "false" |
The injector is configured with the following logic:
- If either label is disabled, the pod is not injected.
- If two labels are enabled, the pod is injected.
Follow the next steps to active java agent injection.
- Label the namespace with
swck-injection=enabled
$ kubectl label namespace default(your namespace) swck-injection=enabled- Add label
swck-java-agent-injected: "true"to the pod, and get the result as below.
$ kubectl get pod -l swck-java-agent-injected=true
NAME READY STATUS RESTARTS AGE
inject-demo 1/1 Running 0 2d2hThe java agent injector supports a precedence order to configure the agent:
Annotations > SwAgent > Configmap (Deprecated) > Default Configmap (Deprecated)
Annotations are described in kubernetes annotations doc.
We support annotations in agent annotations and sidecar annotations.
SwAgent is a Customer Resource defined by SWCK.
We support SwAgent in SwAgent usage guide
Configmap is described in kubernetes configmap doc.
We need to use configmap to set agent.config so that we can modify the agent configuration without entering the container.
If there are different configmap in the namepsace, you can choose a configmap by setting sidecar annotations; If there is no configmap, the injector will create a default configmap.
The injector will create the default configmap to overlay the agent.config in the agent container.
The default configmap is shown as below, one is agent.service_name and the string can't be empty; the other is collector.backend_service and it needs to be a legal IP address and port, the other fields need to be guaranteed by users themselves. Users can change it as their default configmap.
data:
agent.config: |
# The service name in UI
agent.service_name=${SW_AGENT_NAME:Your_ApplicationName}
# Backend service addresses.
collector.backend_service=${SW_AGENT_COLLECTOR_BACKEND_SERVICES:127.0.0.1:11800}
# Please refer to https://skywalking.apache.org/docs/skywalking-java/latest/en/setup/service-agent/java-agent/configurations/#table-of-agent-configuration-properties to get more details.
To avoid the default configmap deleting by mistake, we use a configmap controller to watch the default configmap. In addition, if the user applies an invalid configuration, such as a malformed backend_service, the controller will use the default configmap.
The injector supports two methods to configure agent:
- Only use the default configuration.
- Use annotations to overlay the default configuration.
After activating the java agent injection, if not set the annotations, the injector will use the default agent configuration directly as below.
initContainers:
- args:
- -c
- mkdir -p /sky/agent && cp -r /skywalking/agent/* /sky/agent
command:
- sh
image: apache/skywalking-java-agent:8.16.0-java8
name: inject-skywalking-agent
volumeMounts:
- mountPath: /sky/agent
name: sky-agent
volumes:
- emptyDir: {}
name: sky-agent
- configMap:
name: skywalking-swck-java-agent-configmap
name: java-agent-configmap-volume
The injector will read the SwAgent CR when pods creating.
SwAgent CRD basic structure is like:
apiVersion: operator.skywalking.apache.org/v1alpha1
kind: SwAgent
metadata:
name: swagent-demo
namespace: default
spec:
containerMatcher: ''
selector:
javaSidecar:
name: swagent-demo
image: apache/skywalking-java-agent:8.16.0-java8
env:
- name: "SW_LOGGING_LEVEL"
value: "DEBUG"
- name: "SW_AGENT_COLLECTOR_BACKEND_SERVICES"
value: "skywalking-system-oap:11800"
sharedVolumeName: "sky-agent-demo"
optionalPlugins:
- "webflux"
- "cloud-gateway-2.1.x"
bootstrapPlugins:
- "jdk-threading"There are three kind of configs in SwAgent CR.
label selector and container matcher decides which pod and container should be injected.
| key path | description | default value |
|---|---|---|
| spec.selector | label selector for pods which should be effected during injection. if no label selector was set, SwAgent CR config will affect every pod during injection. | no default value |
| spec.containerMatcher | container matcher is used to decide which container to be inject during injection. regular expression is supported. default value '.*' would match any container name. | .* |
injection configuration will affect on agent injection behaviour
| key path | description | default value |
|---|---|---|
| javaSidecar | javaSidecar is the configs for init container, which holds agent sdk and take agent sdk to the target containers. | |
| javaSidecar.name | the name of the init container. | inject-skywalking-agent |
| javaSidecar.image | the image of the init container. | apache/skywalking-java-agent:8.16.0-java8 |
| SharedVolumeName | SharedVolume is the name of an empty volume which shared by initContainer and target containers. | sky-agent |
| OptionalPlugins | Select the optional plugin which needs to be moved to the directory(/plugins). Such as trace,webflux,cloud-gateway-2.1.x. |
no default value |
| OptionalReporterPlugins | Select the optional reporter plugin which needs to be moved to the directory(/plugins). such as kafka. |
no default value |
| BootstrapPlugins | Select the bootstrap plugin which needs to be moved to the directory(/plugins). such as jdk-threading. |
no default value |
skywalking agent configuration is for agent SDK.
| key path | description | default value |
|---|---|---|
| javaSidecar.env | the env list to be appended to target containers. usually we can use it to setup agent configuration at container level. | no default value. |
The injector can recognize five kinds of annotations to configure the agent as below.
The strategy configuration is the annotation as below.
| Annotation key | Description | Annotation Default value |
|---|---|---|
strategy.skywalking.apache.org/inject.Container |
Select the injected container, if not set, inject all containers. | not set |
The agent configuration is the annotation like agent.skywalking.apache.org/{option}: {value}, and the option support agent.xxx 、osinfo.xxx 、collector.xxx 、 logging.xxx 、statuscheck.xxx 、correlation.xxx 、jvm.xxx 、buffer.xxx 、 profile.xxx 、 meter.xxx 、 log.xxx in agent.config, such as agent.skywalking.apache.org/agent.namespace, agent.skywalking.apache.org/meter.max_meter_size, etc.
The plugins configuration is the annotation like plugins.skywalking.apache.org/{option}: {value}, and the option only support plugin.xxx in the agent.config, such as plugins.skywalking.apache.org/plugin.mount, plugins.skywalking.apache.org/plugin.mongodb.trace_param, etc.
The optional plugin configuration is the annotation as below.
| Annotation key | Description | Annotation value |
|---|---|---|
optional.skywalking.apache.org |
Select the optional plugin which needs to be moved to the directory(/plugins). Users can select several optional plugins by separating from ｜, such as trace｜webflux｜cloud-gateway-2.1.x. |
not set |
The optional reporter plugin configuration is the annotation as below.
| Annotation key | Description | Annotation value |
|---|---|---|
optional-reporter.skywalking.apache.org |
Select the optional reporter plugin which needs to be moved to the directory(/plugins). Users can select several optional reporter plugins by separating from ｜, such as kafka. |
not set |
The bootstrap plugin configuration is the annotation as below.
| Annotation key | Description | Annotation value |
|---|---|---|
bootstrap.skywalking.apache.org |
Select the bootstrap plugin which needs to be moved to the directory(/plugins). Users can select several bootstrap plugins by separating from ｜, such as jdk-threading. |
not set |
The injector can recognize the following annotations to configure the sidecar:
| Annotation key | Description | Annotation Default value |
|---|---|---|
sidecar.skywalking.apache.org/initcontainer.Name |
The name of the injected java agent container. | inject-skywalking-agent |
sidecar.skywalking.apache.org/initcontainer.Image |
The container image of the injected java agent container. | apache/skywalking-java-agent:8.16.0-java8 |
sidecar.skywalking.apache.org/initcontainer.Command |
The command of the injected java agent container. | sh |
sidecar.skywalking.apache.org/initcontainer.args.Option |
The args option of the injected java agent container. | -c |
sidecar.skywalking.apache.org/initcontainer.args.Command |
The args command of the injected java agent container. | mkdir -p /sky/agent && cp -r /skywalking/agent/* /sky/agent |
sidecar.skywalking.apache.org/initcontainer.resources.limits |
The resources limits of the injected java agent container. You should use json type to define it such as {"memory": "100Mi","cpu": "100m"} |
nil |
sidecar.skywalking.apache.org/initcontainer.resources.requests |
The resources requests of the injected java agent container. You should use json type to define it such as {"memory": "100Mi","cpu": "100m"} |
nil |
sidecar.skywalking.apache.org/sidecarVolume.Name |
The name of sidecar Volume. | sky-agent |
sidecar.skywalking.apache.org/sidecarVolumeMount.MountPath |
Mount path of the agent directory in the injected container. | /sky/agent |
sidecar.skywalking.apache.org/env.Name |
Environment Name used by the injected container (application container). | JAVA_TOOL_OPTIONS |
sidecar.skywalking.apache.org/env.Value |
Environment variables used by the injected container (application container). | -javaagent:/sky/agent/skywalking-agent.jar |
Please see javaagent introduction for details.