Limitations and Constraints

• Cross-region resource management is not supported.

  A CBH instance and resources (such as ECSs and cloud databases) managed in the mapped CBH system must be in the same region.

  Although some services such as Cloud Connect (CC) and Virtual Private Network (VPN) can be used to connect VPCs in different regions, using CBH to manage resources across regions is still not recommended because cross-region networks are less stable.

• Cross-VPC resource management is not supported.

  A CBH instance and resources (such as ECSs and cloud databases) managed in the mapped CBH system must be in the same VPC so that the CBH system can communicate the managed resources directly.

  If they are in different VPCs, use a VPC peering connection to connect two VPCs.

• Communication between the CBH instance security group and managed resource security group must be allowed.

  The managed resources must be accessible through the security group to which the CBH instance belongs, and the security group to which the resources belong must allow access from the private IP address of the CBH instance.

  If a CBH instance and its managed resources belong to different security groups, no communication between them is established by default. To establish a connection, add an inbound rule to the CBH instance security group.

  Default ports for a security group: 443 and 2222, which can be accessed through a web browser or SSH client by default. To use other access methods, manually add the destination port.

• A CBH system can be logged in only through IP address and port number.
  Table 1 Inbound and outbound rule configuration reference

  Scenario Description	Direction	Protocol/Application	Port
  Accessing a bastion host through a web browser (HTTP and HTTPS) NOTE: HTTP automatically redirects to HTTPS. For this redirection to work, both port 80 and port 443 must be properly configured.	Inbound	TCP	Ports 80 and 443
  Accessing a bastion host through Microsoft Terminal Services Client (MSTSC)	Inbound	TCP	53389
  Accessing a bastion host through an SSH client	Inbound	TCP	2222
  Accessing a bastion host through an FTP client	Inbound	TCP	2121 and 20000 to 21000
  Accessing a bastion host through an SFTP client	Inbound	TCP	2222
  Remotely accessing Linux cloud servers managed by a bastion host over SSH clients	Outbound	TCP	22
  Remotely accessing Windows cloud servers managed by a bastion host over the RDP protocol	Outbound	TCP	3389
  Accessing Oracle databases through a bastion host	Inbound	TCP	1521
  Accessing Oracle databases through a bastion host	Outbound	TCP	1521
  Accessing MySQL databases through a bastion host	Inbound	TCP	33306
  Accessing MySQL databases through a bastion host	Outbound	TCP	3306
  Accessing SQL Server databases through a bastion host	Inbound	TCP	1433
  Accessing SQL Server databases through a bastion host	Outbound	TCP	1433
  Accessing DB databases through a bastion host	Inbound	TCP	50000
  Accessing DB databases through a bastion host	Outbound	TCP	50000
  Accessing GaussDB databases through a bastion host	Inbound	TCP	18000
  Accessing GaussDB databases through a bastion host	Outbound	TCP	8000 and 18000
  License servers	Outbound	TCP	9443
  Cloud services	Outbound	TCP	443
  Accessing a bastion host system through an SSH client in the same security group	Outbound	TCP	2222
  SMS service	Outbound	TCP	10743 and 443
  Domain name resolution service	Outbound	UDP	53
  Accessing PGSQL databases through a bastion host	Inbound	TCP	15432
  Accessing PGSQL databases through a bastion host	Outbound	TCP	5432
  Accessing DM databases through a bastion host	Inbound	TCP	15236
  Accessing DM databases through a bastion host	Outbound	TCP	5236

• Supported host types

  CBH allows you to manage Linux or Windows hosts with the SSH, RDP, VNC, Telnet, FTP, SFTP, SCP, or Rlogin protocol configured.

• Supported database types
  • Relational Database Service (RDS) DB instances
  • Databases on Elastic Cloud Servers (ECSs)
• Supported database versions
  Table 2 Supported database versions

  Database Engine	Engine Version
  MySQL	5.5, 5.6, 5.7, and 8.0
  Microsoft SQL Server	2014, 2016, 2017, 2019, and 2022
  Oracle	10g, 11g, 12c, 19c, and 21c
  DB2	DB2 Express-C
  PostgreSQL	11, 12, 13, 14, and 15
  GaussDB	2 and 3

• Supported application server types and versions

  Only applications on Windows servers and Linux servers can be managed. Table 3 lists the supported operating system versions.

  Table 3 Supported application server types and versions

  OS Type	Version
  Windows	Windows Server 2008 R2 or later
  Linux	CentOS7.9

  Note

  Currently, application O&M is supported only by x86 CBH instances. Arm CBH instances do not support application O&M.

To perform secure O&M management through CBH, use a third-party client to log in to the CBH system.

• The maximum number of resources that can be managed by CBH cannot exceed the number of assets allowed by the instance edition.
• The maximum number of resources that can be concurrently logged in to through CBH cannot exceed the number of concurrent requests allowed by the CBH instance edition.