@@ -26,7 +26,7 @@ You can download the configuration files in this document from [GitHub](https://
## Configure the service
Create a service configuration file named `taosd-service.yaml`. Record the value of `metadata.name` (in this example, `taos`) for use in the next step. Add the ports required by TDengine:
Create a service configuration file named `taosd-service.yaml`. Record the value of `metadata.name` (in this example, `taos`) for use in the next step. And then add the ports required by TDengine and record the value of the selector label "app" (in this example, `tdengine`) for use in the next step:
```YAML
---
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@@ -50,9 +50,9 @@ spec:
## Configure the service as StatefulSet
According to Kubernetes instructions for various deployments, we will use StatefulSet as the service type of TDengine. Create the file `tdengine.yaml `, where replicas defines the number of cluster nodes as 3. The node time zone is China (Asia/Shanghai), and each node is allocated 5G standard storage (refer to the [Storage Classes ](https://kubernetes.io/docs/concepts/storage/storage-classes/)configuration storage class). You can also modify accordingly according to the actual situation.
According to Kubernetes instructions for various deployments, we will use StatefulSet as the deployment resource type of TDengine. Create the file `tdengine.yaml `, where replicas defines the number of cluster nodes as 3. The node time zone is China (Asia/Shanghai), and each node is allocated 5G standard storage (refer to the [Storage Classes ](https://kubernetes.io/docs/concepts/storage/storage-classes/)configuration storage class). You can also modify accordingly according to the actual situation.
Please pay special attention to the startupProbe configuration, after dnode 's pod drops for a period of time, then restart, this time the newly launched dnode will be temporarily unavailable . If the startupProbe configuration is too small, Kubernetes will think that the Pod is in an abnormal state , and try to restart the Pod, the dnode 's Pod will restart frequently and never return to the normal state . Refer to [Configure Liveness, Readiness and Startup Probes](https://kubernetes.io/docs/tasks/configure-pod-container/configure-liveness-readiness-startup-probes/)
Please pay special attention to the startupProbe configuration. If dnode's Pod drops for a period of time and then restart, the newly launched dnode Pod will be temporarily unavailable. The reason is the startupProbe configuration is too small, Kubernetes will know that the Pod is in an abnormal state and try to restart it, then the dnode's Pod will restart frequently and never return to the normal status. Refer to [Configure Liveness, Readiness and Startup Probes](https://kubernetes.io/docs/tasks/configure-pod-container/configure-liveness-readiness-startup-probes/)
The above configuration will generate a three-node TDengine cluster, dnode is automatically configured, you can use the show dnodes command to view the nodes of the current cluster:
The above configuration will generate a three-node TDengine cluster, dnode is automatically configured, you can use the **show dnodes** command to view the nodes of the current cluster:
The parameter `--replica = 4 `in the above command line indicates that you want to expand the TDengine cluster to 4 nodes. After execution, first check the status of the POD:
The parameter `--replica = 4 `in the above command line indicates that you want to expand the TDengine cluster to 4 nodes. After execution, first check the status of the Pod:
```Bash
kubectl get pod -l app=tdengine -n tdengine-test -o wide
@@ -436,7 +436,7 @@ Query OK, 4 row(s) in set (0.003628s)
## Scaling In Your Cluster
Since the TDengine cluster will migrate data between nodes during volume expansion and contraction, using the kubectl command to reduce the volume requires first using the "drop dnodes" command ( **If there are 3 replicas of db in the cluster, the number of dnodes after reduction must also be greater than or equal to 3, otherwise the drop dnode operation will be aborted** ), the node deletion is completed before Kubernetes cluster reduction.
Since the TDengine cluster will migrate data between nodes during volume expansion and contraction, using the **kubectl** command to reduce the volume requires first using the "drop dnodes" command ( **If there are 3 replicas of db in the cluster, the number of dnodes after reduction must also be greater than or equal to 3, otherwise the drop dnode operation will be aborted** ), the node deletion is completed before Kubernetes cluster reduction.
Note: Since Kubernetes Pods in the Statefulset can only be removed in reverse order of creation, the TDengine drop dnode also needs to be removed in reverse order of creation, otherwise the Pod will be in an error state.
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@@ -453,13 +453,13 @@ taos> show dnodes
Query OK, 3 row(s) in set (0.003324s)
```
After confirming that the removal is successful (use kubectl exec -i -t tdengine-0 --taos -s "show dnodes" to view and confirm the dnode list), use the kubectl command to remove the POD:
After confirming that the removal is successful (use kubectl exec -i -t tdengine-0 --taos -s "show dnodes" to view and confirm the dnode list), use the kubectl command to remove the Pod:
After the POD is deleted, the PVC needs to be deleted manually, otherwise the previous data will continue to be used for the next expansion, resulting in the inability to join the cluster normally.
After the Pod is deleted, the PVC needs to be deleted manually, otherwise the previous data will continue to be used for the next expansion, resulting in the inability to join the cluster normally.
@@ -502,7 +502,7 @@ Query OK, 4 row(s) in set (0.003881s)
## Remove a TDengine Cluster
> **When deleting the pvc, you need to pay attention to the pv persistentVolumeReclaimPolicy policy. It is recommended to change to Delete, so that the pv will be automatically cleaned up when the pvc is deleted, and the underlying csi storage resources will be cleaned up at the same time. If the policy of deleting the pvc to automatically clean up the pv is not configured, and then after deleting the pvc, when manually cleaning up the pv, the csi storage resources corresponding to the pv may not be released.**
> **When deleting the PVC, you need to pay attention to the pv persistentVolumeReclaimPolicy policy. It is recommended to change to Delete, so that the PV will be automatically cleaned up when the PVC is deleted, and the underlying CSI storage resources will be cleaned up at the same time. If the policy of deleting the PVC to automatically clean up the PV is not configured, and then after deleting the pvc, when manually cleaning up the PV, the CSI storage resources corresponding to the PV may not be released.**
Complete removal of TDengine cluster, need to clean up statefulset, svc, configmap, pvc respectively.
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@@ -536,7 +536,7 @@ Query OK, 4 row(s) in set (0.003862s)
For the high availability and high reliability of TDengine in a Kubernetes environment, hardware damage and disaster recovery are divided into two levels:
1. The disaster recovery capability of the underlying distributed Block Storage, the multi-copy of Block Storage, the current popular distributed Block Storage such as CEPH , has the multi-copy capability, extending the storage copy to different racks, cabinets, computer rooms, Data center (or directly use the Block Storage service provided by Public Cloud vendors)
1. The disaster recovery capability of the underlying distributed Block Storage, the multi-copy of Block Storage, the current popular distributed Block Storage such as Ceph, has the multi-copy capability, extending the storage copy to different racks, cabinets, computer rooms, Data center (or directly use the Block Storage service provided by Public Cloud vendors)
2. TDengine disaster recovery, in TDengine Enterprise, itself has when a dnode permanently offline (TCE-metal disk damage, data sorting loss), re-pull a blank dnode to restore the original dnode work.
Finally, welcome to [TDengine Cloud ](https://cloud.tdengine.com/)to experience the one-stop fully managed TDengine Cloud as a Service.
