Differences in the WPAR environment
While the WPAR environment is similar to the environment for an application on a stand-alone system, there are differences that some applications can recognize.
Applications might recognize differences in the following areas:
- Device access
- Some devices are accessible within a WPAR by default. Storage devices might be mounted as file systems from the global environment into the WPAR or they can be exported to the WPAR so that file systems can be created, mounted, or removed from within the WPAR. Storage device adapters might also be exported to a system WPAR which is not a versioned WPAR, giving the WPAR complete control over configuring devices for that adapter.
- Default privilege
- The WPAR root user does not have the same level of access as the root user in the global environment by default.
- Shared kernel
- For applications that provide kernel extensions, the user-level application execution environment is compartmentalized between WPAR instances. However, the shared kernel recognizes all WPAR instances and must maintain the compartmentalization.
- Statistic and tuning virtualization
- While several AIX® system utilities have been enabled to work either fully or partially in a WPAR, there are some utilities that work only in the global environment (for example, the mpstat utility and the sar utility). Because all WPAR instances share the same kernel and certain kernel subsystems are optimized for system-wide usage, it is not possible to tune all kernel subsystem parameters from a WPAR.
- Network configuration
- You cannot modify the network configuration (for example, addresses and routes) inside a WPAR. The default configuration of a WPAR prevents applications from using any raw sockets, but system administrators can enable them.