Scenarios

An ECS group logically groups ECSs. The ECSs in an ECS group comply with the same policy associated with the ECS group.

Only the anti-affinity policy is supported. ECSs in the same ECS group are deployed on different hosts, improving service reliability.

You can use an ECS group to deploy target ECSs on different physical servers to ensure high service availability and underlying DR capabilities.

An ECS group supports the following functions:

• Creating an ECS Group
• Adding an ECS to an ECS Group
  • Add an ECS to an ECS group during ECS creation.
  • Add a created ECS to an ECS group.
• Removing an ECS from an ECS Group
• Deleting an ECS Group

Constraints

• ECS groups support the anti-affinity policy only.
• Target ECSs must be deployed on physical servers.
• The maximum number of ECS groups that can be created is adjustable. Contact customer service to increase the quota.
• The maximum number of ECSs that can be added to an ECS group varies depending on the region. You can view the number on the Elastic Cloud Server page, as shown in Figure 1.
  Figure 1 Maximum number of ECSs that can be added to an ECS group
  

Creating an ECS Group

Create an ECS group to apply the same policy to all group members. ECS groups are independent from each other.

1. Log in to the management console.
2. Click in the upper left corner and select the desired region and project.
3. Under Computing, click Elastic Cloud Server.
4. In the navigation pane on the left, choose ECS Group.
5. On the ECS Group page, click Create ECS Group.
6. Enter an ECS group name.

   The Anti-affinity policy is used by default.

7. Click OK.

Adding an ECS to an ECS Group

After an ECS is added to an ECS group, it can be deployed on a physical server different from the physical servers accommodating other ECSs in the same ECS group.

• The ECS to be added must be stopped.
• After an ECS is added to an ECS group, the system reallocates the physical server accommodating the ECS so that the ECS and other ECSs in the ECS group are deployed on different physical servers. However, when the ECS is restarted, the startup may fail due to insufficient resources. In such a case, remove the ECS from the ECS group and restart the ECS.
• An ECS with local disks attached cannot be added to an ECS group after the ECS is created. To use ECS group functions, select an ECS group during ECS creation.
• An existing ECS cannot be added to an ECS group if it has a local disk attached (for example, a disk-intensive, H2, P1, or P2 ECS), a local NVMe SSD disk attached (for example, of the ultra-high I/O type), a GPU attached (for example, a G3 ECS), or an FPGA attached (for example, an FP1 or FP1c ECS). To use ECS group functions on such ECSs, select an ECS group when creating the ECS.

1. Log in to the management console.
2. Click in the upper left corner and select the desired region and project.
3. Under Computing, click Elastic Cloud Server.
4. In the navigation pane on the left, choose ECS Group.
5. Click Add ECS in the Operation column.
6. On the Add ECS page, select the ECS to be added.
7. Click OK.

Removing an ECS from an ECS Group

After an ECS is removed from an ECS group, the ECS does not comply with the anti-affinity policy anymore.

1. Log in to the management console.
2. Click in the upper left corner and select the desired region and project.
3. Under Computing, click Elastic Cloud Server.
4. In the navigation pane on the left, choose ECS Group.
5. Expand the ECS group information and view the ECSs in the ECS group.
6. Click Remove in the Operation column of the target ECS.
7. Click OK.

   The ECS is removed from the ECS group.

Deleting an ECS Group

After an ECS group is deleted, the policy does not apply to the ECSs in the ECS group anymore.

1. Log in to the management console.
2. Click in the upper left corner and select the desired region and project.
3. Under Computing, click Elastic Cloud Server.
4. In the navigation pane on the left, choose ECS Group.
5. Click Delete in the Operation column of the target ECS group.
6. Click OK.