tencent cloud

Overview

This document describes how to host a Dubbo application to TKE.

Strengths of hosting Dubbo applications to TKE

• Improve the resource utilization.
• Kubernetes is a natural fit for microservice architectures.
• Improve the Ops efficiency and facilitate DevOps implementation.
• Highly scalable Kubernetes makes it easy to dynamically scale applications.
• TKE provides Kubernetes master management to ease Kubernetes cluster Ops and management.
• TKE is integrated with other cloud-native products of Tencent Cloud to help you better use Tencent Cloud products.

Best Practices

The following describes how to host a Dubbo application to TKE by using the Q Cloud Book Mall (QCBM) project as an example.

QCBM overview

QCBM is an online bookstore demo project developed by using the microservice architecture and the Dubbo 2.7.8 framework. It is deployed and hosted on CODING. For more information, see here. QCBM contains the following microservices:

QCBM architecture and add-ons

In the following best practice, applications deployed in CVM are containerized and hosted to TKE. In this use case, one VPC is used and divided into two subnets:

• Subnet-Basic: Deployed with stateful basic services, including Dubbo's service registry Nacos, MySQL, and Redis.
• Subnet-K8S: Deployed with QCBM application services, all of which are containerized and run in TKE.

The VPC is divided as shown below:

The network planning for the QCBM instance is as shown below:

The add-ons used in the QCBM instance are as shown below:

Overview

TCR

Tencent Cloud Tencent Container Registry (TCR) are available in Personal Edition and Enterprise Edition as differentiated below:

QCBM is a Dubbo containerized demo project, so TCR Personal Edition is perfectly suited to its needs. However, for enterprise users, TCR Enterprise Edition is recommended. To use an image repository, see Basic Image Repository Operations.

TSW

Tencent Service Watcher (TSW) provides cloud-native service observability solutions that can trace upstream and downstream dependencies in distributed architectures, draw topologies, and provide multidimensional call observation by service, API, instance, and middleware. It is further described as shown below:

TSW is architecturally divided into four modules:

The architecture is as shown below:

Directions

Building basic service cluster

• In the TencentDB for MySQL console, create an instance and use qcbm-ddl.sql to initialize it. For more information, see Creating MySQL Instance.
• In the TencentDB for Redis console, create an instance and initialize it. For more information, see Creating TencentDB for Redis Instance.
• In the CLB console, create a private network CLB instance for Subnet-K8S (the ID of this CLB instance will be used later). For more information, see Creating CLB Instances.
• Apply for the TSW beta test. TSW is currently in beta test and supports both Java and Go.
• Deploy the Nacos cluster:
  1. In the CVM console, purchase three 1-core 2 GB MEM Standard SA2 CVM instances. For more information, see Creating Instances via CVM Purchase Page.
  2. Log in to the instance and run the following command to install Java.

     yum install java-1.8.0-openjdk.x86_64
     

     Run the following command. If Java version information is output, Java is successfully installed.

     java - version
     

  3. Deploy the Nacos cluster as instructed in Cluster deployment instructions.

Building Docker image

Writing Dockerfile

The following uses user-service as an example to describe how to write a Dockerfile. The project directory structure of user-service is displayed, Dockerfile is in the root directory of the project, and user-service-1.0.0.zip is the packaged file that needs to be added to the image.

➜  user-service tree
├── Dockerfile
├── assembly
│    ....
├── bin
│    ....
├── pom.xml
├── src
│    ....
├── target
│    .....
│   └── user-service-1.0.0.zip
└── user-service.iml

The Dockerfile of user-service is as shown below:

FROM java:8-jre

ARG APP_NAME=user-service
ARG APP_VERSION=1.0.0
ARG FULL_APP_NAME=${APP_NAME}-${APP_VERSION}

# The working directory of the container is `/app`.
WORKDIR /app

# Add the locally packaged application to the image.
COPY ./target/${FULL_APP_NAME}.zip .

# Create the `logs` directory. Decompress and delete the original files and directory after the decompression.
RUN mkdir logs \
      && unzip ${FULL_APP_NAME}.zip \
      && mv ${FULL_APP_NAME}/** . \
      && rm -rf ${FULL_APP_NAME}*

# Start script and parameters of `user-service`
ENTRYPOINT ["/app/bin/user-service.sh"] CMD ["start", "-t"]

# Dubbo port number
EXPOSE 20880

Note：

• Java applications in the production environment have a lot of configuration parameters, making the start script complex. It's a heavy workload to write all the content of the start script to the Dockerfile, which is far less flexible than shell scripts and can't implement fast troubleshooting. We recommend you not enable the start script.
• In general, nohup is used at the end of the start script to start the Java application, but the deamon process that comes along will cause the container to exit directly after execution. Therefore, you need to change nohup java ${OPTIONS} -jar user-service.jar > ${LOG_PATH} 2>&1 & to java ${OPTIONS} -jar user-service.jar > ${LOG_PATH} 2>&1.
• As each Run command in the Dockerfile will generate an image layer, we recommend you combine these commands into one.

Building image

TCR provides both automatic and manual methods to build an image. To demonstrate the build process, the manual method is used.

The image name needs to be in line with the convention of ccr.ccs.tencentyun.com/[namespace]/[ImageName]:[image tag]:

• Here, namespace can be the project name to facilitate image management and use. In this document, QCBM represents all the images under the QCBM project.
• ImageName can contain the subpath, generally used for multi-project use cases of enterprise users. In addition, if a local image is already built, you can run the docker tag command to rename the image in line with the naming convention.

1. Run the following command to build an image as shown below:

   # Recommended build method, which eliminates the need for secondary tagging operations
   sudo docker build -t ccr.ccs.tencentyun.com/[namespace]/[ImageName]:[image tag]
   # Build a local `user-service` image. The last `.` indicates that the Dockerfile is stored in the current directory (`user-service`).
   ➜  user-service docker build -t ccr.ccs.tencentyun.com/qcbm/user-service:1.0.0 .
   # Rename existing images in line with the naming convention
   sudo docker tag [ImageId] ccr.ccs.tencentyun.com/[namespace]/[ImageName]:[image tag]
   

2. After the build is complete, you can run the following command to view all the images in your local repository.

   docker images
   

   A sample is as shown below:
   

Uploading image to TCR

Creating namespace

The QCBM project uses TCR Personal Edition (TCR Enterprise Edition is recommended for enterprise users).

1. Log in to the TKE console.
2. Click TCR > Personal > Namespace to enter the Namespace page.
3. Click Create and create the qcbm namespace in the pop-up window. All the images of the QCBM project are stored under this namespace as shown below:
   

Uploading image

Log in to TCR and upload an image.

1. Run the following command to log in to TCR.

    docker login --username=[Tencent Cloud account ID] ccr.ccs.tencentyun.com
   

   • You can get your Tencent Cloud account ID on the Account Info page.
   • If you forget your TCR login password, you can reset it in My Images of TCR Personal Edition.
     
   • If you are prompted that you have no permission to run the command, add sudo before the command and run it as shown below. In this case, you need to enter two passwords, the server admin password required for sudo and the TCR login password.
     

      sudo docker login --username=[Tencent Cloud account ID] ccr.ccs.tencentyun.com
     

     As shown below:
     

2. Run the following command to push the locally generated image to TCR.

   docker push ccr.ccs.tencentyun.com/[namespace]/[ImageName]:[image tag]
   

   As shown below:
   

3. In My Images, you can view all the uploaded images. The following figure shows the five QCBM images uploaded to TCR.
   

   The default image type is Private. If you want to let others use the image, you can set it to Public in Image Info as shown below:
   

   
   

Deploying service in TKE

Creating K8s cluster of QCBM

1. Before the deployment, you need to create a K8s cluster as instructed in Quickly Creating a Standard Cluster.

   Note：

   When a cluster is created, we recommend you enable Placement Group on the Select Model page. It helps distribute CVM instances across different hosts to increase the system reliability.

2. After the cluster is created, you can view its information on the cluster management page in the TKE console. Here, the new cluster is named qcbm-k8s-demo as shown below:
   
3. Click the Cluster Name to enter the Basic Info page to view the cluster configuration information as shown below:
   
4. (Optional) If you want to use K8s management tools such as kubectl and Lens, you need to follow two steps:
   1. Enable public network access.
   2. Store the API authentication token in the local config file under user home/.kube (choose another if the config file has content) to ensure that the default cluster can be accessed each time. If you choose not to store the token in the config file under .kube, see the Instructions on Connecting to Kubernetes Cluster via kubectl under Cluster API Server Info in the console as shown below:
      

Creating namespace

A namespace is a logical environment in a Kubernetes cluster that allows you to divide teams or projects. You can create a namespace in the following three methods, and method 1 is recommended.

 kubectl create namespace qcbm

shkubctl create –f namespace.yaml

  # Create the `qcbm` namespace.
  apiVersion: v1
  kind: Namespace
  metadata:
    name: qcbm
  spec:
    finalizers:
    - kubernetes

Using ConfigMap to store configuration information

ConfigMap allows you to decouple the configuration from the running image, making the application more portable. The QCBM backend service needs to get the Nacos, MySQL, and Redis host and port information from the environment variables and store them by using ConfigMap.
You can use ConfigMap to store configuration information in the following two methods:

# Create a ConfigMap.

apiVersion: v1
kind: ConfigMap
metadata: 
  name: qcbm-env
  namespace: qcbm
data: 
  NACOS_HOST: 10.0.1.9 
  MYSQL_HOST: 10.0.1.13 
  REDIS_HOST: 10.0.1.16 
  NACOS_PORT: "8848"
  MYSQL_PORT: "3306"
  REDIS_PORT: "6379"
  SW_AGENT_COLLECTOR_BACKEND_SERVICES: xxx   # TSW access address as described below

Using Secret to store sensitive information

A Secret can be used to store sensitive information such as passwords, tokens, and keys to reduce exposure risks. QCBM uses it to store account and password information.
You can use a Secret to store sensitive information in the following two methods:

# Create a Secret.
apiVersion: v1
kind: Secret
metadata: 
  name: qcbm-keys
  namespace: qcbm
  labels: 
    qcloud-app: qcbm-keys
data: 
  # xxx is the Base64-encoded string, which can be generated by using the echo -n raw string | base64 shell command.
  MYSQL_ACCOUNT:  xxx
  MYSQL_PASSWORD: xxx
  REDIS_PASSWORD: xxx
  SW_AGENT_AUTHENTICATION: xxx  # TSW access token as described below
type: Opaque

Deploying Deployment

A Deployment declares the Pod template and controls the Pod running policy, which is suitable for deploying stateless applications. Both front and Dubbo services of QCBM are stateless applications and can use the Deployment.

YAML parameters for the user-service Deployment are as shown below:

A complete sample YAML file for the user-service Deployment is as follows:

# user-service Deployment

apiVersion: apps/v1
kind: Deployment
metadata: 
  name: user-service
  namespace: qcbm
  labels: 
    app: user-service
    version: v1
spec: 
  replicas: 1
  selector: 
    matchLabels: 
      app: user-service
      version: v1
  template: 
    metadata: 
      labels: 
        app: user-service
        version: v1
    spec: 
      containers: 
        - name: user-service
          image: ccr.ccs.tencentyun.com/qcbm/user-service:1.1.4
          env: 
            - name: NACOS_HOST  # IP address of the Dubbo service registry Nacos
              valueFrom: 
                configMapKeyRef: 
                  key: NACOS_HOST
                  name: qcbm-env
                  optional: false
            - name: MYSQL_HOST  # MySQL address
              valueFrom: 
                configMapKeyRef: 
                  key: MYSQL_HOST
                  name: qcbm-env
                  optional: false
            - name: REDIS_HOST  # Redis IP address
              valueFrom: 
                configMapKeyRef: 
                  key: REDIS_HOST
                  name: qcbm-env
                  optional: false
            - name: MYSQL_ACCOUNT  # MySQL account
              valueFrom: 
                secretKeyRef: 
                  key: MYSQL_ACCOUNT
                  name: qcbm-keys
                  optional: false
            - name: MYSQL_PASSWORD  # MySQL password
              valueFrom: 
                secretKeyRef: 
                  key: MYSQL_PASSWORD
                  name: qcbm-keys
                  optional: false
            - name: REDIS_PASSWORD  # Redis password
              valueFrom: 
                secretKeyRef: 
                  key: REDIS_PASSWORD
                  name: qcbm-keys
                  optional: false
            - name: SW_AGENT_COLLECTOR_BACKEND_SERVICES  # SkyWalking backend service address
              valueFrom: 
                configMapKeyRef: 
                  key: SW_AGENT_COLLECTOR_BACKEND_SERVICES
                  name: qcbm-env
                  optional: false
            - name: SW_AGENT_AUTHENTICATION    # Authentication token for SkyWalking Agent to connect to the backend service
              valueFrom: 
                secretKeyRef: 
                  key: SW_AGENT_AUTHENTICATION
                  name: qcbm-keys
                  optional: false
          ports: 
            - containerPort: 20880 # Dubbo port name
              protocol: TCP
      imagePullSecrets:   # The key to pull the image. It is not required as the images of all QCBM services are public.
        - name: qcloudregistrykey

Deploying Service

You can specify the Service type with Kubernetes ServiceType, which defaults to ClusterIP. Valid values of ServiceType include the following:

• LoadBalancer: Provides public network, VPC, and private network access.
• NodePort: : Accesses services through the CVM IP and host port.
• ClusterIP: Accesses services through the service name and port.

For a production system, the gateway needs to be accessible within the VPC or private network, and the front needs to provide access to the private and public networks. Therefore, you need to set ServiceType to LoadBalancer for the QCBM gateway and front.
TKE enriches the LoadBalancer mode by configuring the Service through annotations.

If you use the service.kubernetes.io/qcloud-loadbalancer-internal-subnetid annotations, a private network CLB instance will be created when the Service is deployed. In general, we recommend you create the CLB instance in advance and use the service.kubernetes.io/loadbalance-id annotations in the deployment YAML to improve the efficiency.

The deployment YAML for the qcbm-front Service is as follows:

# Deploy the `qcbm-front` Service.
apiVersion: v1
kind: Service
metadata: 
  name: qcbm-front
  namespace: qcbm
  annotations: 
    # ID of the CLB instance of `Subnet-K8S`
    service.kubernetes.io/loadbalance-id: lb-66pq34pk
spec: 
  externalTrafficPolicy: Cluster
  ports: 
    - name: http
      port: 80
      targetPort: 80
      protocol: TCP
  selector: # Map the backend `qcbm-gateway` to the Service.
    app: qcbm-front
    version: v1
  type: LoadBalancer

Deploying Ingress

An Ingress is a collection of rules that allow external access to the cluster Service, thereby eliminating the need to expose the Service. For QCBM projects, you need to create an Ingress for qcbm-front, which corresponds to the following YAML:

# Deploy the `qcbm-front` Ingress.

apiVersion: networking.k8s.io/v1beta1
kind: Ingress
metadata: 
  name: front
  namespace: qcbm
  annotations: 
    ingress.cloud.tencent.com/direct-access: "false"
    kubernetes.io/ingress.class: qcloud
    kubernetes.io/ingress.extensiveParameters: '{"AddressIPVersion":"IPV4"}'
    kubernetes.io/ingress.http-rules: '[{"host":"qcbm.com","path":"/","backend":{"serviceName":"qcbm-front","servicePort":"80"}}]'
spec: 
  rules: 
    - host: qcbm.com
      http: 
        paths: 
          - path: /
            backend:  # Associate with backend services.
              serviceName: qcbm-front
              servicePort: 80

Viewing deployment result

So far, you have completed the deployment of QCBM in TKE and can view the deployment result in the following steps:

1. Log in to the TKE console and click the Cluster ID/Name to enter the cluster details page.
2. Click Services and Routes > Ingress to enter the Ingress page, where you can see the created Ingress. You can access the QCBM page through the Ingress VIP.

Integrating CLS

Enabling container log collection

The container log collection feature is disabled by default and needs to be enabled as instructed below:

1. Log in to the TKE console and click Cluster Ops > Feature Management on the left sidebar.
2. At the top of the Feature Management page, select the region. On the right of the target cluster, click Set.
   
3. On the Configure Features page, click Edit for log collection and select Enable Log Collection as shown below:
   
4. Click OK.

Creating log topic and logset

QCBM is deployed in Nanjing region, so you need to select Nanjing region when creating logsets:

1. Log in to the CLS console and select Nanjing region on the Log Topic page.
2. Click Create Log Topic and enter the relevant information in the pop-up window as prompted as shown below:
   
   

• Log Topic Name: Enter qcbm.
• Logset Operation: Select Create Logset.
• Logset Name: Enter qcbm-logs.

3. Click OK.

   Note：

   As QCBM has multiple backend microservices, you can create a log topic for each microservice to facilitate log categorization.

   • A log topic is created for each QCBM service.
   • You need the log topic ID when creating log rules for containers.

Configuring log collection rule

You can configure container log collection rules in the console or with CRD.

apiVersion: cls.cloud.tencent.com/v1
kind: LogConfig
metadata: 
  name: user-log-rule
spec: 
  clsDetail: 
 extractRule: {}
 # Single-line text
 logType: minimalist_log
 # ID of the user-log log topic
 topicId: 0c544491-03c9-4ed0-90c5-9bedc0973478
  inputDetail: 
 # The container, workload, and log output directory where the logs are located
 containerFile: 
   container: user-service
   filePattern: '*.log'
   logPath: /app/logs
   namespace: qcbm
   workload: 
     kind: deployment
     name: user-service
 # The log collection type is the container file path.
 type: container_file

Viewing log

1. Log in to the CLS console and enter the Search and Analysis page.
2. On the Search and Analysis page, Create Index for the logs first and then click Search and Analysis to view the logs.
   

Note：

You can't find logs if no indexes are created.

Integrating TSW

TSW is currently in beta test and can be deployed in Guangzhou and Shanghai. Here, Shanghai is used as an example (QCBM is deployed in Nanjing).

Accessing TSW - getting access point information

1. Log in to the TSW console and click Service Observation > Service List on the left sidebar.
2. Click Access Service and select Java and the SkyWalking data collection method. The access method provides the Access Point and Token information.

Accessing TSW - application and container configuration

Enter the Access Point and Token of the TSW obtained in the previous step in collector.backend_service and agent.authentication respectively in the agent.config of SkyWalking. agent.service_name is the service name, and agent.namespace can be used to group microservices under the same domain. user-service configuration is as shown below:

You can also configure SkyWalking Agent by using environment variables. QCBM uses the ConfigMap and Secret to configure environment variables:

• Use the ConfigMap to configure SW_AGENT_COLLECTOR_BACKEND_SERVICES.
• Use the Secret to configure SW_AGENT_AUTHENTICATION.

As shown below:

At this point, you have completed TSW access. After starting the container service, you can view the call chain, service topology, and SQL analysis in the TSW console.

Using TSW

Viewing call exception through service API or call chain

1. Log in to the TSW console and click Service Observation > API Observation on the left sidebar.
2. On the API Observation page, you can view the call status of all APIs under a service, including the number of requests, success rate, error rate, response time, and other metrics.

Using TSW to analyze add-on (such as SQL and caching) call

1. Log in to the TSW console and click Add-on Call Observation > SQL Call on the left sidebar.
2. On the SQL Call page, you can view the call details of SQL, NoSQL, MQ, and other add-ons. For example, you can quickly locate frequent SQL requests and slow queries in your application with the number and durations of SQL requests.

Viewing service topology

1. Log in to the TSW console and click Chain Tracing > Distributed Dependency Topology on the left sidebar.
2. On the Distributed Dependency Topology page, you can view the completed service dependencies as well as information such as the number of calls and average latency.