Migrating Symantec Veritas Cluster Server to HP Serviceguard for Linux

Technical white paper | Migrating Symantec Veritas Cluster Server to HP Serviceguard for Linux
Following are the possible values for dependency location in VCS:
• Local dependency: The parent service group depends on the child service group for being online or offline on the
same system.
• Global dependency: An instance of the parent service group depends on one or more instances of the child service group
being online on any system in the cluster.
• Remote dependency: An instance of the parent service group depends on one or more instances of the child service
group being online on any system in the cluster other than the system on which the parent service group is online.
Following are the corresponding possible values for dependency location in SG/LX:
• same_node: It means that the dependency must be satisfied on the same node.
• any_node: It means that the dependency can be satisfied on any node in the cluster.
• different_node: It means that the dependency must be satisfied on a node other than the dependent package’s node.
Following are the possible values for the dependency rigidity in VCS:
• Soft dependency: It specifies the minimum constraints while bringing parent and child groups online.
• Firm dependency: It imposes more constraints when VCS brings the parent or child groups online or takes them offline.
• Hard dependency: It imposes the maximum constraints when VCS brings the parent of child service groups online or
takes them offline.
There is no configurable parameter in SG/LX cluster to define the rigidity of a dependency. The VCS firm dependency rigidity
is the closest equivalent for SG/LX package dependency rigidity.
Mapping VCS resources to Serviceguard modules
In VCS, you can include resources in a service group and use corresponding resource agent for monitoring. For example IP
resource agent, filesystem resource agent, mount resource agent, and others. You can define the order in which the
resources can start and stop by defining dependency among resources.
In Serviceguard, you can also include resources in a package by including corresponding resource module. For example,
modules of volume group, IP, filesystem, and others. These modules only start and stop the resources. For monitoring the
resources, you can configure generic resources in the SG/LX package. To configure a generic resource, a monitoring script
needs to be written which can monitor the resource and set the status of generic resource. SG/LX recommends launching
the monitoring scripts by configuring them as services in a package.
Mapping VCS user privileges and roles to SG/LX access control policy parameters
Cluster operations are enabled or restricted depending on the privileges with which you log on. VCS has three privilege
levels: Administrator, Operator, and Guest. VCS provides some predefined user roles; each role has specific privilege levels.
For example, the role Guest has the fewest privileges and the role Cluster Administrator has the most privileges.
In SG/LX, you can also enable or restrict the uses by defining access control policy parameters. Following three parameters
are used to achieve this:
• user_name: It can either be “any_user” or a maximum of eight login names from the/etc/passwd file on user host.
• user_host: It is where the user can issue Serviceguard commands. It can be “any_serviceguard_node”, or (any)
“cluster_member_node”, or a specific node.
• user_role: It can have one of the following three values:
– MONITOR: read-only capabilities for the cluster and packages
– PACKAGE_ADMIN: MONITOR, plus administrative privileges for packages in the cluster
– FULL_ADMIN: MONITOR and PACKAGE_ADMIN plus the administrative privileges for the cluster
Mapping VCS system capacity and service group load to Serviceguard node capacity and package weight
The VCS capacity construct enables you to define a fixed amount of resources a server can provide. It sets a fixed
load-handling capacity for servers. The Load attribute allows you to define a fixed amount of resources a specific service
group is expected to utilize (Load). It sets a fixed demand for service groups. When a service group is brought online, its load
is subtracted from the system’s capacity to determine available capacity. VCS maintains this info in the attribute Available
Capacity. When a failover occurs, VCS determines which system has the highest available capacity and starts the service
group on that system.
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