63 lines
1.5 KiB
Markdown
63 lines
1.5 KiB
Markdown
# Health Check
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Health check intends to provide a unique approach to check the healthy status of OAP server. It includes the health status
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of modules, GraphQL and gRPC services readiness.
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## Health Checker Module.
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Health Checker module could solute how to observe the health status of modules. We can active it by below:
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```yaml
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health-checker:
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selector: ${SW_HEALTH_CHECKER:default}
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default:
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checkIntervalSeconds: ${SW_HEALTH_CHECKER_INTERVAL_SECONDS:5}
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```
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Notice, we should enable `telemetry` module at the same time. That means the provider should not be `-` and `none`.
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After that, we can query OAP server health status by querying GraphQL:
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```
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query{
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checkHealth{
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score
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details
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}
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}
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```
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If the OAP server is healthy, the response should be
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```json
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{
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"data": {
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"checkHealth": {
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"score": 0,
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"details": ""
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}
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}
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}
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```
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Once some modules are unhealthy, for instance, storage H2 is down. The result might be like below:
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```json
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{
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"data": {
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"checkHealth": {
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"score": 1,
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"details": "storage_h2,"
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}
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}
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}
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```
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You could refer to [checkHealth query](https://github.com/apache/skywalking-query-protocol/blob/master/common.graphql)
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for more details.
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## The readiness of GraphQL and gRPC
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We could opt to above query to check the readiness of GraphQL.
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OAP has implemented [gRPC Health Checking Protocol](https://github.com/grpc/grpc/blob/master/doc/health-checking.md).
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We could use [grpc-health-probe](https://github.com/grpc-ecosystem/grpc-health-probe) or any other tools to check the
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health of OAP gRPC services.
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