Pandora: Documentation en: Architecture

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1 The Pandora FMS Architecture

This chapter provides a general description of Pandora FMS and its components, the way they relate to each other and how to use the Pandora FMS architecture to meet different challenges regarding the topology of its infrastructure.

Pandora FMS can be modular and decentralized or simple and monolithic. The most vital component is the MySQL database, where all the information is stored. Each component of Pandora FMS can be replicated and works in a pure HA environment, be it passive, active or in a clustered environment (Active/Active with load balancing).

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Diagram of the global architecture of Pandora FMS


Pandora FMS consists of several elements, among them, the ones that are in charge of collecting and processing the data, which are the Servers. The servers, with the information generated by them or by the agents, enter the data into the database. The console is the part in charge of displaying the data that are present in the database and interacting with the end user. Software Agents are applications that run on monitored systems, and collect the information to send it to Pandora FMS servers.

1.1 Pandora FMS Servers


Under Pandora FMS, there are twelve different servers in total, specialized in and responsible for the various tasks necessary to make Pandora what it is today. The servers are integrated into a single application under the general name of 'Pandora Server' which is a multi-threaded application (multi-processing) that executes in sub-processes (threads) each one being different to the instances or to the specialized servers of Pandora FMS.

The Pandora FMS Server is the element in charge of performing the pertinent checks. It verifies and changes them according to their results. They are also responsible for triggering the alerts that are set to monitor the status of data.

The Pandora FMS Data Server can work with high availability and / or load balancing. In a very large architecture it is possible to employ several servers simultaneously to handle large volumes of information, and may be distributed by geographic or functional zones.

The Pandora FMS Server is always working and verifying if any monitored elements are experiencing any difficulties and can take appropriate action(s) if those are defined as alerts. When faced with a problem, it executes the response defined in the alert, such as sending an SMS, an email or activating the execution of a script.

There can be simultaneous servers, one of them being a main server and the rest of the servers being slaves. Although there is a master and a slave server relationship, they work simultaneously. The difference between the two is that when a server of the same type is down (e. g. a network server) the master server is in charge of processing all the data associated with the server that is down.

The server receiving the data file from the agent, or processing the information (if this is of the remote type) is the one which fires the associated alerts after the data is processed.

Pandora FMS automatically manages each server's status, load levels and other parameters. The user can monitor the state of each server by the server's status section of the web console.

1.1.1 The Data Server


It processes the information sent by the Software agents. The Software agents collect information locally from the systems on which they are installed and build an information packet in XML format. These XML packets are sent to the server. On the server, they are received in a specific directory, the server processes all the files that are coming to this input directory and stores the information in the database.

Different data servers can be installed on different systems or on the same host (which will be different virtual servers). Several servers can work together for very large environments that need to make better use of hardware (e. g. in multi-CPU environments).

Despite its simplicity and scarce use of resources, the data server is one of the critical elements of the system, since it processes all agent information and generates alerts and system events according to those data. The data server only works with the data that arrives in XML from the software agents and does not perform any kind of remote verification.

1.1.2 The Network Server


It executes remote monitoring tasks through the network: ICMP checks (Ping, latency time), TCP requests and SNMP requests. When an agent is assigned to a server, the network server that will run the checks for that agent is being specified, so it is very important that the machines running the network servers have "network visibility" in order to be able to execute the network monitoring tasks assigned to them. That is, if you're going to ping systems on a particular network, the network server can get to that network:

For example, if a module is created to perform a ping check at 192.168.1.1 and this agent/module is assigned to a server on a 192.168.2.0/24 network without network access 192.168.1.0/24 it will always return DOWN as it cannot contact it.

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1.1.3 The SNMP Trap Console


The SNMP Server utilizes the standard daemon of the traps collection system called 'snmptrapd'. This daemon receives SNMP traps and the Pandora FMS Server processes and stores them in the database. While processing and analyzing them, it can also fire the designated alerts on the SNMP Pandora FMS console.

1.1.4 The WMI Server


WMI is a Microsoft standard to obtain information from a Windows-based operating system and Microsoft Windows environmental applications. Pandora FMS has a server dedicated to conduct native centralized WMI calls. Thanks to that server it's possible to collect data from Windows systems remotely and without the need for an agent.

1.1.5 The Recon Server


The Recognition Server (or 'Recon Server') is used to explore the network regularly and to detect new systems in operation. The Recon Server is also able to assign a monitoring template to recently detected systems and to apply the modules automatically by default, as defined by that template, so they can immediately be used to monitor the new system. By using the applications of the NMAP, xprobe and traceroute systems, it's also capable of identifying systems by their operating system, based on the opened ports and to establish the network's topology, guided by the systems it already knows.

1.1.6 The Plugin Server


The Plugin Server runs complex checks remotely using custom scripts. They can be developed in any language and integrated in the Pandora FMS interface, being managed centrally. This allows an advanced user to define their own complex tests, developed by themselves, and integrate them in the application so that they can be used in a comfortable and centralized way from Pandora FMS.

1.1.7 The Prediction Server


The Prediction Server is a small component of artificial intelligence that implements a statistically predicted data set which is based on past data with a scope of up to 30 days in four temporal references. This allows us to predict the value of a data item in 10 to 15 minute intervals, making an educated assumption whether a particular data set presents an anomaly. At present, it's based on its past historical performance. You basically won't have to construct a dynamic baseline by a weekly profile.

This server also manages the calculation of the services monitoring (BPM) from Pandora FMS version 5.0. onwards.

1.1.8 The web server (Goliat)

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The Web Server (Goliat), the Export Server, the Inventory Server, the Event Correlation Server and the Enterprise Network Server are all features which are only available on the Enterprise Version of Pandora FMS.

 


The Web Server is used to carry out transactional web monitoring. It conducts synthetic network testing, which means complete network testing, including user identification process, parameters for data transfer, contents verification, menu navigation, etc. It's basically intended for verification tests and to obtain latencies (in seconds) of the complete network navigation experience (including the resources linked to the page, like images, full texts, etc).

1.1.9 The Export Server

(Enterprise version only)

The Export Server of Pandora FMS permits the transfer of data from the monitored dispositive of a Pandora FMS installation to another, making it possible to facilitate replication of any data. This is particularly useful for large deployments with several Pandora FMS installations, for example, if we want to have some critical information centralized in only one of them.

1.1.10 The Inventory Server

(Enterprise version only)

The Inventory Server obtains and visualizes inventory information on the systems: Installed software and patches, hardware, memory, hard disks, services running on the system, etc. It's able to obtain this information both locally and remotely from the software agents.

1.1.11 The Event Correlation Server

(Enterprise version only)

The Event Correlation Server can be used to correlate events and generate alerts. This is a special server that does not monitor, and like the others, this can be specified in the configuration for its start up. Compared to the rest, this server does not make use of the threads configuration or high availability.

1.1.12 The Enterprise Network Server for SNMP and ICMP

(Enterprise version only)

There are two additional servers using advanced strategies to process ICMP (ping) and SNMP (polling) requests in a way that offers superior performance than the open-source version, in exchange for some delicate requests (especially SNMP) as they work with previously validated OID’s by the open server.

1.1.13 Satellite server

This component is installed separately to the main server of Pandora FMS. It allows to explore and detect new systems, remotely monitor with ICMP and SNMP high speed, and it executes remote plugins and allows the forwarding of data files from software agents to the main server, acting as agent proxy. It sends monitoring data as XMLs over a tentacle connection, so no database connection is required.

You can read more about this in the specific section about Distributed monitoring with Satellite server

1.1.14 WUX server

It is a server, which combined with the Selenium Grid, allows complex WEB transactions to be carried out in a distributed manner. It differs from simple WEB checks (Goliat) in that these transactions are executed in a real browser, and their output is captured and processed to visualize it step by step, including captures of errors, as well as detailed statistics of all WEB requests.

1.2 The Pandora FMS Network Console


This is the Pandora FMS User Interface. This administration and operations console allows the user to control the status of the agents, access statistical information, generate graphics and tables of data, as well as managing incidences with its integrated system serving different users with different privileges. It is also capable of producing reports and defining new modules, agents and alerts as well as creating other user profiles - and all of that is centralized from the interface.

The web console is programmed in PHP and does not require any additional software to be installed by the end user. It can be accessed from any modern platform that supports HTML and CSS. Firefox 2. x or Chrome is recommended. The user experience with browsers such as Internet Explorer 6 is very poor, and essential console functionality may be lost.

The network console is able to operate and supervise multiple servers. This means you may add as many web consoles as you want, either for load distribution or to facilitate access due to logistical problems (large networks, several groups with different users, geographical and administrative differences, etc.) Its only requirement is to be able to access the data container where Pandora FMS stores everything: the database, and in the case of the Enterprise version, to access the agent configuration repository in a synchronized way (via NFS).

1.3 The Pandora FMS Database


Pandora FMS uses a MySQL database in which it stores all the information received in real time, normalizing all the data of the different source sources. It conforms the most important and critical component of any Pandora FMS installation, containing not only the information and historical data, but all the configurations made over time. In the past PostgreSQL and Oracle were supported, but now only MySQL/MariaDB/Percona are supported.

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La base de datos es el núcleo de Pandora FMS


This data is managed automatically from Pandora FMS, carrying out a periodical and automatic maintenance of the database, not being necessary any kind of database administration task nor manual process assisted by an operator or administrator. This is done by periodic purging of the data on a due date.

1.4 The Software Agents of Pandora FMS


When we refer to an agent in Pandora FMS it is important to differentiate two concepts.

  • The Agent, or agent in console, as container.
  • The Software Agent, as software that runs on a computer.

1.4.1 The Agent (container)

The Pandora FMS agent itself is basically an organizational element, created with Pandora FMS Web Console and associated with a group of modules (seen as individual monitoring elements). This agent can also (optionally) have one or more IP addresses associated to it.

The agent can have associated remote modules, which would have been obtained by web servers, WMIs, plug ins, etc.

  • Verification of whether the engine is connected or on line (PING).
  • Verification of whether a given port is opened or closed.
  • Verification of whether a network entity, hosted on a specific port of the hardware, is responding correctly.
  • Verification of whether a network entity, hosted on a specific point of the hardware, has the desired content.
  • Hardware verification(s) by SNMP (ascertaining the MIB).
  • Latency time verification between the node and the Pandora FMS servers.

The agent can also have local type modules associated to it. Local modules are those defined in the software agent's configuration which are also required to be defined within the network console's agent. If the agent is in 'auto-learning mode' (the default setting), these local modules are created automatically in the web console when a data packet arrives from the agent for the first time.

Therefore, an 'Agent' may contain modules of both remote and local types. The remote-type modules are executed by the servers obtaining information remotely (prediction included) and the local modules are obtained by the Data Server.

1.4.2 The Software Agent

The software agents are installed on the computers that want to monitor themselves locally, extracting the information from the computer itself. They are mainly used in servers for monitoring machine resources (CPU, RAM, disks...) and installed applications (MySQL, Apache, JBoss...). Generally, monitoring of servers and equipment will be carried out with software agents, while monitoring of network equipment will be done remotely without the installation of any software.


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Illustration: Collection of Data in Pandora FMS

Each software agent performs several checks, called modules, where each of them correspond to a specific data, such as CPU usage. All the information of the checks carried out is captured in a single data file in XML format that is sent to Pandora FMS server.

The process of copying the data packet from the agent to the server is done regularly (Synchronous) every so often, this interval is defined in the software agent, which initiates communications with the server.

The interval can be defined up to 300 seconds, which is the decimal equivalent of 5 minutes. Lesser values to 100 (seconds) are not recommended, as they can negatively affect the host-system's performance. Such a low polling time can overload the database and the central processing system.

It's important to remember that Pandora FMS is not a 'eal time system, but a general monitoring system for systems and applications in environments where real time is not a critical factor. It may be adapted to operate in environments with response times of 3 to 5 seconds.


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Illustration: Logical diagram of an agent and a physical agent.

Packet transfers are conducted by the Tentacle Protocol, but they can also be transferred using SSH or FTP.

With either SSH or Tentacle, the process can be made secure, given that passwords don't travel through the network nor do they contain unencrypted confidential data, assuring the confidentiality, integrity and authentication of the connections between agent and server. The code-generating process and also the Tentacle protocol are detailed in the documentation on the installation and configuration of the agents and servers to be able to carry out the SCP (SSH) transfer automatically.

The transfer may also be conducted by FTP or any other file transfer protocols. However, we chose the Tentacle Protocol due to its security, user friendliness and the numerous options this system provides.

Please check the documentation annex regarding configuration of other transfer protocols.

Pandora FMS agents are designed to be executed from the agent they collect the data from, although the agents can also collect information stored in accessible engines from the host they are installed on. These are known as 'satellite agents'.

1.4.3 The XML Data File

This data file contains an XML structure and its name is formed by combining the hostname or host where the agent is located, a different serial number for each data packet and the .data extension indicating that it is a data packet.

<host number>.<serial number>.data 


Illustration: Logical structure of a software agent's modules.
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The ".data" file is the file which holds the data. The verification file with the ".checksum" extension contains an MD5 hash of the data file. These allow us to perform a final verification to ensure the data hasn't been altered in any way before being processed.

<host number>.<serial number>.checksum

The XML data file contains all the information gathered by the Agent during its execution. This data packet has a compact, flexible and light design that allows that any user can use Pandora FMS agents or its own developments to generate information and that it be processed in Pandora FMS. The data file is an XML similar to the following:

 <agent data os_name=”SunOS” os_version=”5.8” timestamp=”300” agent_name=”pdges01” version=”1.0”>
 <module>
 <name>FTP Daemon</name>
 <type>generic_proc</type>
 <data>0</data>
 </module>
 <module>
 <name>DiskFree</name>
 <type>generic_data</type>
 <data>5200000</data>
 </module>
 <module>
 <name>UsersConnected</name>
 <type>generic_data_inc</type>
 <data>119</data>
 </module>
 <module>
 <name>LastLogin</name>
 <type>generic_data_string</type>
 <data>slerena</data>
 </module>
 </agent_data>

1.5 Topologies, Schemes and Monitoring Models

There are different models to address the monitoring process, both local and remote. We enumerate the following common examples for different topologies in order to familiarize the reader with the possible problems and the solutions Pandora has to offer. Each of the solutions is described in successive chapters.

1.5.1 Accessible Networks

This is the norm in small, simple networks but also in the very centralized and well organized ones. This one is the easiest model to implement.

  • Network access for centralized remote monitoring. It implies that we can access every node from Pandora’s server to probe remotely.
  • Network access for agent based monitoring. In this network, we're able to reach Pandora’s server from the agents installed on the monitoring engine.

1.5.2 Limited-Access Networks

  • Remote Network: This is an unreachable network for remote testing by Pandora FMS. In this scenario we have several options, either the use of a software agent that runs remote checks towards other systems (using the broker modality), or using the Satellite Server, which is capable of executing remote checks and has a series of advanced functionalities.
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Deployment model for remote and inaccessible networks in Broker Mode


  • Software agents without access to a Pandora FMS Server. In this case, we're going to use the proxy characteristics of the software agents, allowing those agents without direct access to the server to use another agent with direct access to connect, forwarding the XML files of all other agents of their own. The Satellite Server can also act as a proxy agent.
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Deployment model for remote networks by using the Proxy Agent Mode


  • The need to conduct remote server monitoring for different networks: In this case we can also make use of the Satellite Server, or mount several different Pandora FMS servers connected to the same database, one server will run a set of checks, and another server another different set. The way to perform the deployment will be different but in both cases each component will be fully responsible for the monitoring of your network and management will be centralized from the Console.


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Remote network deployment model using the Satellite Server


1.5.3 Special Organizational Characteristics

  • The need to have "" several sites monitored "", with different monitoring equipment and configurations. In this case we will use an Export Server to duplicate part of the monitoring in a segregated Pandora FMS environment, which is independent.
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Hierarchical export model along with an Export Server


  • Duality of Reporting: Additionally, we can configure agents to report to two different Pandora FMS servers, although they can only be managed by one of them.
  • Fragmented Management: It's pretty useful if you're required to delegate the administration of part of the equipment to different personnel with different access levels. This is more of a management issue rather than an architectural problem. It can be resolved by the assigned permissions within the management policies.

1.5.4 Large Environments

  • A Large-Volume Network, consisting of thousands of network testing processes which we distribute within different 'remote monitoring probes'. Given their large numbers (over 50,000) we can't centralize them into a single server. To facilitate monitoring we're going to use different servers in Broker Mode which distributes the monitoring by its own method.


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Distribution of remote testing model with agents in broker mode

  • The need to mount a server on HA for security reasons, in case primary hardware fails. We will see how to mount two servers, one "passive", waiting for the asset to stop responding and start up. There are different ways to do this.
  • The need to monitor a large volume of systems and manage them in a centralized way (more than 2500 agents). In order to do so, we're configuring different Pandora FMS Servers, coordinated by the system we call 'metaconsole'. They can be linearly scaled in this way.


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The metaconsole model

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