Zenoss Glossary

This glossary should be useful for users who need a reference for the occasional clarification as well as developers who need an explicit and detailed understanding of terms varying contexts.

Data Collection

These are the terms related to the data collection process. The Zope product responsible for this areas of Zenoss is the DataCollector

Collecting - the process of obtaining information from networked resources, devices, hosts and their operating systems.

Collector Client - since the information obtained during the Collecting process are networked resources, we need clients to to connect to these resources and this is what the Collector Client does. Each client usually wraps some amount of lower-level Twisted Python networking code.

Data Collector - this is the zenmodeler, the brains behind Collecting.

Data Map - after networked resource data is collected, it needs to be parsed and presented to the Zenoss system. This parsed data is stored in a Data Map and is used to keep track of changes in networked resources.

Plugins - plugins for Data Collection tell the Collector Clients what information to get from the networked resources.

Daemon

In Unix and other computer multitasking operating systems, a daemon is a computer program that runs in the background, rather than under the direct control of a user; they are usually instantiated as processes. Typically daemons have names that end with the letter "d"; for example, syslogd is the daemon which handles the system log. Daemons typically do not have any existing parent process, but reside directly under init in the process hierarchy. Daemons usually become daemons by forking a child process and then making the parent process kill itself, thus making init adopt the child. This practice is commonly known as "fork off and die." Systems often start (or "launch") daemons at boot time: they often serve the function of responding to network requests, hardware activity, or other programs by performing some task. Daemons can also configure hardware (like devfsd on some Linux systems), run scheduled tasks (like cron), and perform a variety of other tasks.

Debian

Debian, organized by the Debian Project, is a widely used distribution of free software developed through the collaboration of volunteers from around the world. Since its inception, the released system, Debian GNU/Linux, has been based on the Linux kernel, with many basic tools of the operating system from the GNU project. Debian is known for its adherence to the Unix and free software philosophies, and for its abundance of options — the current release includes over fifteen thousand software packages for eleven computer architectures, ranging from the ARM architecture commonly found in embedded systems and the IBM s390 mainframe architecture to the more common x86 and PowerPC architectures found in modern personal computers. Debian GNU/Linux is the basis for several other distributions, including Knoppix and Ubuntu.

Device

A device is defined as a Zenoss code abstraction for a combination of a networked resources hardware and that hardware's operating system. Any piece of hardware attached to a network you want to monitor using Zenoss. These can include: printers, servers, routers, and switches among others.

Event

An event can be defined as "a significant change in state or any action or occurrence detected by a program. Events can be user actions, such as clicking a mouse button or pressing a key, or system occurrences, such as running out of memory. State changes for objects can create also create events.

GPL

The GNU General Public License (GNU GPL or simply GPL) is a widely used free software license.

ICMP

Short for Internet Control Message Protocol, an extension to the Internet Protocol (IP) defined by RFC 792. ICMP supports packets containing error, control, and informational messages. The PING command, for example, uses ICMP to test an Internet connection.

Severity

Levels of Severity is how events within the Zenoss System are classified. The scale is as follows: Color = Severity Red = Critical Orange = Error Yellow = Warning Blue = Information Grey = Debug

Management Information Base

A management information base (MIB) is a type of database used to manage the devices in a communications network. It comprises a collection of objects in a (virtual) database used to manage entities (such as routers and switches) in a network. Objects in the MIB are defined using a subset of Abstract Syntax Notation One (ASN.1) called "Structure of Management Information Version 2 (SMIv2)" RFC 2578.The software that performs the parsing is an MIB compiler. The database is hierarchical (tree structured) and entries are addressed through object identifiers. Internet documentation RFCs discuss MIBs, notably RFC 1155, "Structure and Identification of Management Information for TCP/IP based internets", and its two companions, RFC 1213, "Management Information Base for Network Management of TCP/IP-based internets", and RFC 1157, "A Simple Network Management Protocol".

Modeling

A model is the collection of code abstractions (python objects) that represents actual networked resources. Modeling (creating a model of a) a piece of hardware in your system consists of gathering all of that date possible about that device and creating a device profile based upon that data. This model can be supplemented by hand entered data that is of particular use in creating a more accurate profile (model) of the device. This information can also be re-used to assist in the modeling of hardware producing similar data.

Object Identifier

In the context of SNMP, consists of the object identifier for an object in a Management Information Base (MIB).

RRDTemplate

The top level performance configuration object is an RRDTemplate. RRDTemplates define the data sources to collect, any thresholds and how the data sources should be graphed. RRDTemplates are defined in the PerfConf tab of any device tree object or on the collected object itself.

Simple Network Management Protocol

A set of protocols for managing complex networks. The first versions of SNMP were developed in the early 80s. SNMP works by sending messages, called protocol data units (PDUs), to different parts of a network. SNMP-compliant devices, called agents, store data about themselves in Management Information Bases (MIBs) and return this data to the SNMP requesters.

SNMP Walk

The operation performed using SNMP to gather information about a specific device.

sudo

sudo (substitute user [or superuser] do), pronounced like sudo in sudoku, is a program in Unix, Linux, and similar operating systems such as Mac OS X that allows users to run programs with the security privileges of another user (normally the system's superuser) in a secure manner. Users must confirm their identity to sudo by supplying their password before running the target program. Once authentication has taken place, and if /etc/sudoers file is configured to give the user access to the command requested, then the system allows the command, but logs it. In a GUI environment, graphical frontends such as kdesu and gksudo are used to launch administrator-only applications like the Synaptic Package Manager. Ubuntu Linux is well-known for forcing all administrative access to be done via sudo – the root password is disabled by default, but can be enabled via the passwd tool. Mac OS X also uses sudo for tasks such as Software Update. The configuration file /etc/sudoers specifies which users can run which commands, and on which machines. Because sudo is very particular about the format of this configuration file, and errors could cause serious problems, editing should always be done with the provided visudo or sudoedit tool, which checks for correctness before saving.

SUSE Linux Enterprise Server

SUSE Linux Enterprise Server (SLES) is a Linux distribution supplied by Novell, targeted at the business market. It is supposed to be run mainly on servers, but some desktop software is included as well. New versions are released at an interval of 18-24 months. During that period the selected software is put under heavy testing with the intention that only mature, stable versions of the included components will make it through to the released product.

Ubuntu

Ubuntu is a Linux distribution offering an operating system predominantly targeted at personal computers. Based on Debian GNU/Linux, Ubuntu concentrates on usability, freedom from restriction of use, regular releases, and ease of installation.

Virtual Appliance

A virtual appliance is a minimalist virtual machine image designed to run under VMware, providing network applications such as webservers. Virtual appliances are a subset of the broader class of software appliances. Like software appliances, virtual appliances are aimed to eliminate the installation, configuration and maintenance costs associated with running complex stacks of software. A key concept that differentiates a virtual appliance from a virtual machine is that a virtual appliance is a fully pre-installed and pre-configured application and operating system environment whereas a virtual machine is, by itself, without software Typically a virtual appliance will have a web interface to configure the inner workings of the appliance. A virtual appliance is usually built to host a single application, and so represents a new way of deploying network applications. See also VMWare.

VMware – Virtual Machine ware

VMware refers to the computer and operating-system instance that executes the VMware Workstation process as the host machine, and identifies instances of operating systems (or of virtual appliances) running inside a virtual machine as guest virtual machines. Like an emulator, VMware Workstation provides a completely virtualized set of hardware to the guest operating system — for example, regardless of make and model of the physical network adapter, the guest machine will see an AMD PCnet network adapter. VMware virtualizes all devices within the virtual environment, including the video adapter, network adapter, and hard disk adapters. It also provides pass-through drivers for USB, serial, and parallel devices.