[skywalking-cli] 01/01: Update README.md

[ha...@apache.org]

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hanahmily pushed a commit to branch gao-ch
in repository https://gitbox.apache.org/repos/asf/skywalking-cli.git

commit f8dabae1cd876e2a99aaa12f3bf2df953f00193f
Author: Gao Hongtao <ha...@gmail.com>
AuthorDate: Thu Aug 6 23:29:28 2020 +0800

    Update README.md
    
    Document check health subcommand.
---
 README.md | 44 ++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 44 insertions(+)

diff --git a/README.md b/README.md
index 3b6de38..dc6d043 100644
--- a/README.md
+++ b/README.md
@@ -279,6 +279,26 @@ You can imitate the content of [the default template file](example/Dashboard.Glo
 
 </details>
 
+</details>
+
+### `checkHealth`
+
+<details>
+
+<summary>checkHealth [--grpc=true/false] [--grpcAddr=host:port] [--grpcTLS=true/false]</summary>
+
+`dashboard global-metrics` displays global metrics in the form of a dashboard.
+
+| argument | description | default |
+| :--- | :--- | :--- |
+| `--grpc` | Enable/Disable check gRPC endpoint | `true` |
+| `--grpcAddr` | The address of gRPC endpoint | `127.0.0.1:11800` |
+| `--grpcTLS` | Enable/Disable TLS to access gRPC endpoint | `false` |
+
+*Notice: Once enable gRPC TLS, checkHealth command would ignore server's cert.
+
+</details>
+
 # Use Cases
 
 <details>
@@ -547,6 +567,30 @@ $ ./bin/swctl --debug --timezone="0" service ls
 
 </details>
 
+<details>
+
+<summary>Check whether OAP server is healthy</summary>
+
+if you want to check health status from GraphQL and the gRPC endpoint listening on 10.0.0.1:8843. 
+
+```shell
+$ ./bin/swctl checkHealth --grpcAddr=10.0.0.1:8843
+```
+
+If you only want to query GraphQL.
+
+```shell
+$ ./bin/swctl checkHealth --grpc=false
+```
+
+Once the gRPC endpoint of OAP encrypts communication by TLS.
+
+```shell
+$ ./bin/swctl checkHealth --grpcTLS=true
+```
+
+</details>
+
 # Contributing
 For developers who want to contribute to this project, see [Contribution Guide](CONTRIBUTING.md)