This Steadybit extension provides a jvm instance discovery and the various actions for jvm instances targets.
Learn about the capabilities of this extension in our Reliability Hub.
Environment Variable | Helm value | Meaning | Required | Default |
---|---|---|---|---|
STEADYBIT_EXTENSION_RUNTIME |
container.runtime |
The container runtime to user either docker , containerd or cri-o . Will be automatically configured if not specified. |
yes | (auto) |
STEADYBIT_EXTENSION_SOCKET |
containerRuntimes.(docker/containerd/cri-o).socket |
The socket used to connect to the container runtime. Will be automatically configured if not specified. | yes | (auto) |
STEADYBIT_EXTENSION_CONTAINERD_NAMESPACE |
The containerd namespace to use. | yes | k8s.io | |
STEADYBIT_EXTENSION_RUNC_ROOT |
containerRuntimes.(docker/containerd/cri-o).runcRoot |
The runc root to use. | yes | (auto) |
STEADYBIT_EXTENSION_RUNC_DEBUG |
Activate debug mode for run. | |||
STEADYBIT_EXTENSION_JVM_ATTACHMENT_ENABLED |
is jvm attachment enabled | no | true | |
STEADYBIT_EXTENSION_JAVA_AGENT_ATTACHMENT_PORT |
java agent attachment port | no | 8095 | |
STEADYBIT_EXTENSION_CONTAINER_ADDRESS |
public ip of the extension | no | ||
STEADYBIT_EXTENSION_DISCOVERY_ATTRIBUTES_EXCLUDES_JVM |
discovery.attributes.excludes.jvm |
List of Target Attributes which will be excluded during discovery. Checked by key equality and supporting trailing "*" | false |
The extension supports all environment variables provided by steadybit/extension-kit.
When installed as linux package this configuration is in/etc/steadybit/extension-jvm
.
The capabilities needed by this extension are: (which are provided by the helm chart)
SYS_ADMIN
SYS_RESOURCE
SYS_PTRACE
KILL
NET_ADMIN
DAC_OVERRIDE
SETUID
SETGID
AUDIT_WRITE
To be able to discover we need access to the java process. This is done by using the attach
mechanism of the JVM. This
is a standard mechanism and is used by many other tools.
You may see a warning in the logs of the JVM that the extension is attaching to the JVM. This is normal and expected.
It will look like this:
WARNING: A Java agent has been loaded dynamically (...javaagent-init.jar)
WARNING: Dynamic loading of agents will be disallowed by default in a future release
To avoid this warning or be able to use this extension in future java releases you can use the
-XX:+EnableDynamicAgentLoading
flag in your JVM commandline to be able to load the javaagent dynamically.
In order to discover the spring boot applications correctly you need to enable some JMX beans and set an application name.
Add these to your application.properties
:
spring.application.name=my-application-name
spring.jmx.enabled=true
management.endpoints.jmx.exposure.include=beans,mappings
Detailed information about agent and extension installation in kubernetes can also be found in our documentation.
All extensions provide a helm chart that is also integrated in the helm-chart of the agent.
The extension is installed by default when you install the agent.
You can provide additional values to configure this extension.
--set extension-jvm.container.runtime={{YOUR-CONTAINER-RUNTIME}} \
Additional configuration options can be found in the helm-chart of the extension.
If you need more control, you can install the extension via its dedicated helm-chart.
helm repo add steadybit-extension-jvm https://steadybit.github.io/extension-jvm
helm repo update
helm upgrade steadybit-extension-jvm \
--install \
--wait \
--timeout 5m0s \
--create-namespace \
--namespace steadybit-agent \
--set container.runtime=docker \
steadybit-extension-jvm/steadybit-extension-jvm
Please use our agent-linux.sh script to install the extension on your Linux machine. The script will download the latest version of the extension and install it using the package manager.
After installing, configure the extension by editing /etc/steadybit/extension-jvm
and then restart the service.
Make sure that the extension is registered with the agent. In most cases this is done automatically. Please refer to the documentation for more information about extension registration and how to verify.
We try to limit the access needed for the extension to the absolute minimum. So the extension itself can run as a non-root user on a read-only root file-system and will, by default, if deployed using the provided helm chart.
In order to execute certain actions the extension needs extended capabilities, see details below.
For discovery the extension needs access to the container runtime socket.
The JVM attachment reuses the target container's linux namespace(s), control group(s) and user.
This requires the following capabilities:
SYS_ADMIN
, SYS_RESOURCE
, SYS_PTRACE
, KILL
, NET_ADMIN
, DAC_OVERRIDE
, SETUID
, SETGID
, AUDIT_WRITE
Add the steadybit.agent.disable-jvm-attachment
flag to your JVM commandline like in this example:
java -Dsteadybit.agent.disable-jvm-attachment -jar spring-boot-sample.jar --server.port=0