OpenSolaris and UNIX System V system administration pragmatics: service startup, dependencies, management, system updates

System administration is an important aspect of managing any operating system, and OpenSolaris is no exception. In this article, we will discuss some of the pragmatic approaches to system administration in OpenSolaris, including service startup, dependencies, management, and system updates.

Service Startup:

One of the primary tasks of system administration is to manage the startup of various services on the system. In OpenSolaris, this is done using the Service Management Facility (SMF). SMF provides a uniform and consistent way to manage services across the system. SMF is based on the concept of service instances, where each service is defined as an instance of a service contract. Service contracts define the characteristics of the service, including its dependencies, runtime properties, and logging information.

SMF provides a number of commands that allow administrators to manage services. The svcs command lists the current status of all services, while the svcadm command can be used to enable, disable, or restart services. For example, to enable the ssh service on the system, the following command can be used:

     # svcadm enable ssh   

Dependencies:

Services in OpenSolaris can have dependencies on other services or resources. For example, the Apache web server may depend on the availability of a database service. SMF allows administrators to specify these dependencies using service contracts. When a service is started, SMF will automatically start any dependent services that are not already running.

Management:

In addition to startup and dependency management, system administrators need to be able to monitor and manage the overall health of the system. OpenSolaris provides a number of tools and utilities that can be used for this purpose. The System Monitoring Tools (SMT) provide a graphical interface for monitoring system performance and resource usage. The Solaris Management Console (SMC) provides a centralized interface for managing services, user accounts, and other system settings.

System Updates:

Keeping the system up-to-date with the latest security patches and bug fixes is an important aspect of system administration. OpenSolaris provides a number of tools to help administrators manage system updates. The Image Packaging System (IPS) is used to manage the installation and removal of software packages on the system. IPS provides a command-line interface, as well as a graphical interface through the Package Manager application.

One of the unique features of OpenSolaris is the concept of boot environments. A boot environment is a snapshot of the system at a particular point in time, including the operating system, configuration files, and installed software. Boot environments are used to provide a safe way to perform system updates, as well as a way to rollback changes if a problem occurs.

When a system update is performed using IPS, a new boot environment is created automatically. The updated packages are installed into the new boot environment, leaving the original boot environment unchanged. The new boot environment can be activated at any time, allowing administrators to switch to the updated environment and test the changes before making them permanent.

In conclusion, OpenSolaris provides a number of pragmatic approaches to system administration, including service management, dependency management, monitoring and management, and system updates. The Service Management Facility provides a uniform and consistent way to manage services across the system, while the Image Packaging System allows administrators to manage software updates. The concept of boot environments provides a safe and reliable way to perform system updates and rollback changes if necessary. These tools and utilities make OpenSolaris a powerful and flexible operating system for enterprise environments.