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K8STARS

K8STARS is a convenient solution to run TARS services in kubernetes.

Characteristics

• Maintain the native development capability of TARS
• Automatic registration and configuration deletion of name service for TARS
• Support smooth migration of original TARS services to K8S and other container platforms
• Non intrusive design, no coupling relationship with operating environment

Implementation scheme

1. Three interfaces are added in the tarsregistry, which are used for automatic registration, heartbeat reporting and node offline. For details, please refer to interface definition。

2. A 'tarscli' command-line tool is provided to allocate ports, generate configuration, report heartbeat and node offline.

Deployment examples

1. Tarsregistry (name service for TARS Project) Refer to the instructions in baseserver to deploy tarsregistry

2. Deployment service example -Deploy sample simpleserver

   cd examples/simple && kubectl apply -f simpleserver.yaml

   Example description:

   • The image is created by the examples / simple / dockerfile file, and the basic image is created by cmd/tarscli/dockerfile
   • start.sh: tarscli genconf in is used to generate the tars service startup configuration
   • server_ meta.yaml The file is used to configure the metadata of the service. For field information, please refer to app/genconf/config.go structure ServerConf . Endpoint defaults to tcp -h ${local_ip} -p ${random_port} , supports automatic filling of IP and random ports. -ased on Golang HelloWorld program TestApp.HelloGo See examples/README.md

3. Verify the deployment Login db_tars , then execute select * from t_server_conf\G The node information of simpleserver has been registered automatically.

Tars deployment directory structure

tarscli based on environment variable TARS_PATH(default/tars) to manage services. The directory functions are as follows:

• ${TARS_PATH}/bin：Startup scripts and binaries
• ${TARS_PATH}/conf：Configuration file
• ${TARS_PATH}/log： Log file
• ${TARS_PATH}/data：Runtime, Cache file

About tarscli

tarscli provides a set of command tools to facilitate container deployment of TARS services. Parameters can be specified through environment variables. For details, see tarscli help.

Here are the sub commands supported by tarscli

• genconf is used to generate the startup configuration file of the TARS service. The supported environment variables are:

• TARS_Application the application name specified. By default, the_ server_ meta.yaml Read from

• TARS_Server is the service name specified by the_ server_ meta.yaml Read from

• TARS_BUILD_Server the service name at compile time. It will be used when the compiled service name is different from the running service name

• TARS_LOCATOR can specify the address of registry. The default is tars.tarsregistry.QueryObj@tcp -h tars-registry.default.svc.cluster.local -p 17890 (address of service)

• TARS_SET_ID can specify service set

• TARS_MERGE_Conf can specify the configuration template file and merge the configuration into the service startup configuration file

• supervisor executes the genconf command by default, and then starts and monitors the service. The supported environment variables are:

• TARS_START_PATH The startup script of the service $TARS_PATH/bin/start.sh

• TARS_STOP_PATH The stop script, by default, kill all service processes under path $TARS_PATH

• TARS_REPORT_INTERVAL reports the interval heartbeat to registry

• TARS_DISABLE_FLOW whether to enable traffic when registering with registry. If it is not empty, it means it is off. It is enabled by default

• TARS_CHECK_INTERVAL check the service status interval. If the status changes, it will be synchronized to the registry in real time

• TARS_BEFORE_CHECK_SCRIPT the shell command that runs before each check

• TARS_CHECK_SCRIPT_TIMEOUT the timeout to run the shell command before each check

• TARS_PRESTOP_WAITTIME turn off traffic - the waiting time before stopping the service. It is used for lossless changes. The default value is 80 seconds

• Hzcheck is used to synchronize the service status and the pod status of k8s. You need to set the readiness probe of pod to tarscli hzcheck command

• Prestop is used to delete the configuration corresponding to the registry before the service exits

  • TARS_PRESTOP_WAITTIME turn off traffic - the waiting time before stopping the service. It is used for lossless changes. The default value is 80 seconds

• Notify is used to send management commands. The common commands are: tars.setloglevel/tars.pprof, etc

Basic services

TARS related basic services provide rich service governance functions. Please refer to baseserver for deployment.