使用Helm部署TDengine集群

Helm 是 Kubernetes 的包管理器，上一节中的操作已经足够简单，但Helm依然可以提供更强大的能力。

安装 Helm

curl -fsSL -o get_helm.sh \
  https://raw.githubusercontent.com/helm/helm/master/scripts/get-helm-3
chmod +x get_helm.sh
./get_helm.sh

Helm 会使用 kubectl 和 kubeconfig 的配置来操作 Kubernetes，可以参考 Rancher 安装 Kubernetes 的配置来进行设置。

安装 TDengine Chart

TDengine Chart 尚未发布到 Helm 仓库，当前可以从GitHub直接下载：

wget https://github.com/taosdata/TDengine-Operator/raw/3.0/helm/tdengine-3.0.2.tgz

获取当前 Kubernetes 的存储类：

kubectl get storageclass

在 minikube 默认为 standard.

之后，使用helm命令安装：

helm install tdengine tdengine-3.0.2.tgz \
  --set storage.className=<your storage class name>

在 minikube 环境下，可以设置一个较小的容量避免超出磁盘可用空间：

helm install tdengine tdengine-3.0.2.tgz \
  --set storage.className=standard \
  --set storage.dataSize=2Gi \
  --set storage.logSize=10Mi

部署成功后，TDengine Chart将会输出操作TDengine的说明：

export POD_NAME=$(kubectl get pods --namespace default \
  -l "app.kubernetes.io/name=tdengine,app.kubernetes.io/instance=tdengine" \
  -o jsonpath="{.items[0].metadata.name}")
kubectl --namespace default exec $POD_NAME -- taos -s "show dnodes; show mnodes"
kubectl --namespace default exec -it $POD_NAME -- taos

您可以自行尝试一下，就像这样：

可以创建一个表进行测试：

kubectl --namespace default exec $POD_NAME -- \
  taos -s "create database test;
    use test;
    create table t1 (ts timestamp, n int);
    insert into t1 values(now, 1)(now + 1s, 2);
    select * from t1;"

Values 配置

TDengine 支持 values.yaml 自定义。

通过 helm show values 可以获取TDengine Chart支持的全部values列表：

helm show values tdengine-3.0.2.tgz

你可以将结果保存为 values.yaml，之后可以修改其中的各项参数，如 replica 数量，存储类名称，容量大小，TDengine 配置等，然后使用如下命令安装 TDengine 集群：

helm install tdengine tdengine-3.0.2.tgz -f values.yaml

全部参数如下：

# Default values for tdengine.
# This is a YAML-formatted file.
# Declare variables to be passed into helm templates.

replicaCount: 1

image:
  prefix: tdengine/tdengine
  #pullPolicy: Always
  # Overrides the image tag whose default is the chart appVersion.
#  tag: "3.0.0.0"

service:
  # ClusterIP is the default service type, use NodeIP only if you know what you are doing.
  type: ClusterIP
  ports:
    # TCP range required
    tcp: [6030, 6041, 6042, 6043, 6044, 6046, 6047, 6048, 6049, 6060]
    # UDP range
    udp: [6044, 6045]


# Set timezone here, not in taoscfg
timezone: "Asia/Shanghai"

resources:
  # We usually recommend not to specify default resources and to leave this as a conscious
  # choice for the user. This also increases chances charts run on environments with little
  # resources, such as Minikube. If you do want to specify resources, uncomment the following
  # lines, adjust them as necessary, and remove the curly braces after 'resources:'.
  # limits:
  #   cpu: 100m
  #   memory: 128Mi
  # requests:
  #   cpu: 100m
  #   memory: 128Mi

storage:
  # Set storageClassName for pvc. K8s use default storage class if not set.
  #
  className: ""
  dataSize: "100Gi"
  logSize: "10Gi"

nodeSelectors:
  taosd:
    # node selectors

clusterDomainSuffix: ""
# Config settings in taos.cfg file.
#
# The helm/k8s support will use environment variables for taos.cfg,
# converting an upper-snake-cased variable like `TAOS_DEBUG_FLAG`,
# to a camelCase taos config variable `debugFlag`.
#
# See the variable list at https://www.taosdata.com/cn/documentation/administrator .
#
# Note:
# 1. firstEp/secondEp: should not be setted here, it's auto generated at scale-up.
# 2. serverPort: should not be setted, we'll use the default 6030 in many places.
# 3. fqdn: will be auto generated in kubenetes, user should not care about it.
# 4. role: currently role is not supported - every node is able to be mnode and vnode.
#
# Btw, keep quotes "" around the value like below, even the value will be number or not.
taoscfg:
  # Starts as cluster or not, must be 0 or 1.
  #   0: all pods will start as a seperate TDengine server
  #   1: pods will start as TDengine server cluster. [default]
  CLUSTER: "1"

  # number of replications, for cluster only
  TAOS_REPLICA: "1"


  #
  # TAOS_NUM_OF_RPC_THREADS: number of threads for RPC
  #TAOS_NUM_OF_RPC_THREADS: "2"

  #
  # TAOS_NUM_OF_COMMIT_THREADS: number of threads to commit cache data
  #TAOS_NUM_OF_COMMIT_THREADS: "4"

  # enable/disable installation / usage report
  #TAOS_TELEMETRY_REPORTING: "1"

  # time interval of system monitor, seconds
  #TAOS_MONITOR_INTERVAL: "30"

  # time interval of dnode status reporting to mnode, seconds, for cluster only
  #TAOS_STATUS_INTERVAL: "1"

  # time interval of heart beat from shell to dnode, seconds
  #TAOS_SHELL_ACTIVITY_TIMER: "3"

  # minimum sliding window time, milli-second
  #TAOS_MIN_SLIDING_TIME: "10"

  # minimum time window, milli-second
  #TAOS_MIN_INTERVAL_TIME: "1"

  # the compressed rpc message, option:
  #  -1 (no compression)
  #   0 (all message compressed),
  # > 0 (rpc message body which larger than this value will be compressed)
  #TAOS_COMPRESS_MSG_SIZE: "-1"

  # max number of connections allowed in dnode
  #TAOS_MAX_SHELL_CONNS: "50000"

  # stop writing logs when the disk size of the log folder is less than this value
  #TAOS_MINIMAL_LOG_DIR_G_B: "0.1"

  # stop writing temporary files when the disk size of the tmp folder is less than this value
  #TAOS_MINIMAL_TMP_DIR_G_B: "0.1"

  # if disk free space is less than this value, taosd service exit directly within startup process
  #TAOS_MINIMAL_DATA_DIR_G_B: "0.1"

  # One mnode is equal to the number of vnode consumed
  #TAOS_MNODE_EQUAL_VNODE_NUM: "4"

  # enbale/disable http service
  #TAOS_HTTP: "1"

  # enable/disable system monitor
  #TAOS_MONITOR: "1"

  # enable/disable async log
  #TAOS_ASYNC_LOG: "1"

  #
  # time of keeping log files, days
  #TAOS_LOG_KEEP_DAYS: "0"

  # The following parameters are used for debug purpose only.
  # debugFlag 8 bits mask: FILE-SCREEN-UNUSED-HeartBeat-DUMP-TRACE_WARN-ERROR
  # 131: output warning and error
  # 135: output debug, warning and error
  # 143: output trace, debug, warning and error to log
  # 199: output debug, warning and error to both screen and file
  # 207: output trace, debug, warning and error to both screen and file
  #
  # debug flag for all log type, take effect when non-zero value\
  #TAOS_DEBUG_FLAG: "143"

  # generate core file when service crash
  #TAOS_ENABLE_CORE_FILE: "1"

扩容

关于扩容可参考上一小节的说明，有一些额外的操作需要从 helm 的部署中获取。

首先，从部署中获取 StatefulSet 的名称。

export STS_NAME=$(kubectl get statefulset \
  -l "app.kubernetes.io/name=tdengine" \
  -o jsonpath="{.items[0].metadata.name}")

扩容操作极其简单，增加replica即可。以下命令将TDengine扩充到三节点：

kubectl scale --replicas 3 statefulset/$STS_NAME

使用命令 show dnodes show mnodes 检查是否扩容成功：

缩容

缩容操作并没有完整测试，可能造成数据风险，请谨慎使用。

相较与上一小节，缩容也需要额外的步骤。

获取需要缩容的dnode列表，并手动Drop。

kubectl --namespace default exec $POD_NAME -- \
  cat /var/lib/taos/dnode/dnodeEps.json \
  | jq '.dnodeInfos[1:] |map(.dnodeFqdn + ":" + (.dnodePort|tostring)) | .[]' -r
kubectl --namespace default exec $POD_NAME -- taos -s "show dnodes"
kubectl --namespace default exec $POD_NAME -- taos -s 'drop dnode "<you dnode in list>"'

清理

Helm管理下，清理操作也变得简单：

helm uninstall tdengine

但Helm也不会自动移除PVC，需要手动获取PVC然后删除掉。