Configuring Data Storage

Scenario

EVS Disks

1. When deploying an application component, choose Advanced Settings > Component Configuration on the Configure Component page.
2. Choose Data Storage > Cloud Storage > Add Cloud Storage and set parameters by referring to Table 2.

   Table 2 EVS disks

   Parameter	Description
   Storage Type	Select EVS disk. The method of using an EVS disk is the same as that of using a traditional disk. However, EVS disks have higher data reliability and I/O throughput and are easier to use. They apply to file systems, databases, or other system software or workloads that require block storage devices.
   Storage Allocation Mode	Manual Select a created storage. Automatic A storage is created automatically. You need to enter the storage capacity. If Storage Class is set to EVS Disk, select an AZ for creating the EVS disk first. Select a storage sub-type. High I/O: EVS disks that have high I/O and use SAS. Common I/O: EVS disks that use SATA. Ultra-high I/O: EVS disks that have ultra-high I/O and use SSD. Enter the storage capacity, in the unit of GB. Ensure that the storage capacity quota is not exceeded; otherwise, creation will fail.
   Add Docker Mounting	Set Mounting Path: Enter the application path to which the data volume is mounted. NOTICE: Do not mount a data volume to a system directory such as / or /var/run. Otherwise, an exception occurs. An empty directory is recommended. If the directory is not empty, ensure that the directory does not contain any file that affects application startup. Otherwise, the files will be replaced, causing application startup exceptions. As a result, the application fails to be created. When the data volume is mounted to a high-risk directory, you are advised to use a low-permission account to start the application; otherwise, high-risk files on the host may be damaged. Set Permission. Read-only: allows you only to read data volumes in the application path. Read/Write: allows you to modify data volumes in the application path. To prevent data loss, newly written data will not be migrated during application migration.

3. Click OK.

HostPath

The file or directory of the host is mounted to the application component.

1. When deploying an application component, choose Advanced Settings > Component Configuration on the Configure Component page.
2. Choose Data Storage > Local Disk > Add Local Disk and set parameters by referring to Table 3.

   Table 3 HostPath

   Parameter	Description
   Local Disk Type	Select HostPath.
   Host Path	Enter the host path, for example, /etc/hosts.
   Docker Mounting	Set Mounting Path: Enter the application path to which the data volume is mounted. NOTICE: Do not mount a data volume to a system directory such as / or /var/run. Otherwise, an exception occurs. An empty directory is recommended. If the directory is not empty, ensure that the directory does not contain any file that affects application startup. Otherwise, the files will be replaced, causing application startup exceptions. As a result, the application fails to be created. When the data volume is mounted to a high-risk directory, you are advised to use a low-permission account to start the application; otherwise, high-risk files on the host may be damaged. Set Permission. Read-only: allows you only to read data volumes in the application path. Read/Write: allows you to modify data volumes in the application path. To prevent data loss, newly written data will not be migrated during application migration.

3. Click OK.

EmptyDir

EmptyDir applies to temporary data storage, disaster recovery, and shared running. It will be deleted upon deletion or transfer of application component instances.

1. When deploying an application component, choose Advanced Settings > Component Configuration on the Configure Component page.
2. Choose Data Storage > Local Disk > Add Local Disk and set parameters by referring to Table 4.

   Table 4 EmptyDir

   Parameter	Description
   Local Disk Type	Select EmptyDir.
   Disk Media	If you select Memory, the running speed is improved, but the storage capacity is limited by the memory size. This mode applies to a small amount of data with high requirements on reading and writing efficiency. If Memory is not selected, data is stored in disks, which is applicable to a large amount of data with low requirements on reading and writing efficiency.
   Docker Mounting	Set Mounting Path: Enter the application path to which the data volume is mounted. NOTICE: Do not mount a data volume to a system directory such as / or /var/run. Otherwise, an exception occurs. An empty directory is recommended. If the directory is not empty, ensure that the directory does not contain any file that affects application startup. Otherwise, the files will be replaced, causing application startup exceptions. As a result, the application fails to be created. When the data volume is mounted to a high-risk directory, you are advised to use a low-permission account to start the application; otherwise, high-risk files on the host may be damaged. Set Permission. Read-only: allows you only to read data volumes in the application path. Read/Write: allows you to modify data volumes in the application path. To prevent data loss, newly written data will not be migrated during application migration.

3. Click OK.

ConfigMap

ServiceStage separates the application codes from configuration files. ConfigMap is used to process application component configuration parameters.

1. When deploying an application component, choose Advanced Settings > Component Configuration on the Configure Component page.
2. Choose Data Storage > Local Disk > Add Local Disk and set parameters by referring to Table 5.

   Table 5 ConfigMap

   Parameter	Description
   Local Disk Type	Select ConfigMap.
   Configuration Item	Select the desired configuration item name. Create a configuration item. For details, see Creating a Configuration Item.
   Docker Mounting	Set Mounting Path: Enter the application path to which the data volume is mounted. NOTICE: Do not mount a data volume to a system directory such as / or /var/run. Otherwise, an exception occurs. An empty directory is recommended. If the directory is not empty, ensure that the directory does not contain any file that affects application startup. Otherwise, the files will be replaced, causing application startup exceptions. As a result, the application fails to be created. When the data volume is mounted to a high-risk directory, you are advised to use a low-permission account to start the application; otherwise, high-risk files on the host may be damaged. Set Permission. Read-only: allows you only to read data volumes in the application path. Read/Write: allows you to modify data volumes in the application path. To prevent data loss, newly written data will not be migrated during application migration.

3. Click OK.

Secret

The data in the secret is mounted to the specified application component. The content of the secret is user-defined.

1. When deploying an application component, choose Advanced Settings > Component Configuration on the Configure Component page.
2. Choose Data Storage > Local Disk > Add Local Disk and set parameters by referring to Table 6.

   Table 6 Secret

   Parameter	Description
   Local Disk Type	Select Secret.
   Secret Item	Select the desired secret name. For details about how to create a secret, see Creating a Secret.
   Docker Mounting	Set Mounting Path: Enter the application path to which the data volume is mounted. NOTICE: Do not mount a data volume to a system directory such as / or /var/run. Otherwise, an exception occurs. An empty directory is recommended. If the directory is not empty, ensure that the directory does not contain any file that affects application startup. Otherwise, the files will be replaced, causing application startup exceptions. As a result, the application fails to be created. When the data volume is mounted to a high-risk directory, you are advised to use a low-permission account to start the application; otherwise, high-risk files on the host may be damaged. Set Permission. Read-only: allows you only to read data volumes in the application path. Read/Write: allows you to modify data volumes in the application path. To prevent data loss, newly written data will not be migrated during application migration.

3. Click OK.