1. 1. Asterisk from beginning to advanced (part 3) Part 3 Used: Debian 8 libreoffice Email: m.gh@linuxmail.org License: GPLV3 Get latest version of this slides and see Other projects and tutorials: https://github.com/m-gh/
2. 2. Start asteriskStart asterisk By default, starting Asterisk will run it in the background: Command: root@localhost:/#asterisk In order to connect to a running Asterisk process, you can attach a remote console using the -r option: root@localhost:/#asterisk -r To disconnect from a connected remote console, simply hit Ctrl+C: You can start Asterisk in the foreground, with an attached root console, using the -c option: root@localhost:/#asterisk -c
3. 3. Adding Verbosity: Asterisk provides a number of mechanisms to control the verbosity of its logging. One way in which this can be controlled is through the command line parameter -v. For each -v specified, Asterisk will increase the level of VERBOSE messages by 1. The following will create a console and set the VERBOSE message level to 2: root@localhost:/#asterisk -c -v -v root@localhost:/#asterisk -rvvv More Options There are many more command line options available. For more information, use the -h option: # asterisk -h Start asteriskStart asterisk
4. 4. Asterisk Command Line InterfaceAsterisk Command Line Interface What is the CLI? The Command Line Interface, or console for Asterisk, serves a variety of purposes for an Asterisk administrator. Obtaining information on Asterisk system components Affecting system configuration Seeing log output, errors and warnings in real-time Generating calls for testing Viewing embedded help documentation such as for APIs, applications, functions and module configuration
5. 5. Connecting to the Asterisk CLIConnecting to the Asterisk CLI There are two ways to connect to an Asterisk console, either a foreground console when starting the Asterisk process (asterisk -c) or by connecting to a remote console after Asterisk is already running (asterisk -r).
6. 6. File sizesFile sizes Files generated by various Asterisk modules or core features may grow to significant sizes depending on how you use Asterisk and the configuration of those sub- systems. Systems that may generate large files are: Logging Reporting Audio recording applications. The key is to know where these components store their output and to have some mechanism in place to prevent the files from growing.
7. 7. It is in the interest of every Asterisk administrator to perform due diligence for security concerns. Most security measures are a matter of configuration and prevention, however for a production system already running there are a few things to consider in the context of maintenance. The Asterisk Security Event Logger can generate log output for security events. You may want to monitor these manually or have scripts and applications that take action on these events or log messages. Be aware of security vulnerability announcements. There are a few places these are announced: http://www.asterisk.org/downloads/security-advisories. SecuritySecurity
8. 8. Backing up Asterisk DataBacking up Asterisk Data Backing up Asterisk is not a complex task. Mostly, you just need to know where the files are and then employ common tools for archiving and storing those files somewhere. Files to consider for backup: Asterisk configuration Asterisk internal DB Other database used by Asterisk Asterisk logs and reports you might set up a cron job in Linux to regularly perform that process and send the files off-site. In general, use whatever backup processes you use for any other Linux applications that you manage. Restoring a backup, in most cases should be as simple as placing the files back in their original locations and starting Asterisk.
9. 9. LoggingLogging Logging in Asterisk is a powerful mechanism that can be utilized to extract vital information from a running system. Logging in Asterisk is configured in the logger.conf file. See Logging Configuration page for more information.
10. 10. Hangup and show channels in CLIHangup and show channels in CLI newtonr-laptop*CLI> core show channels Channel Location State Application(Data) SIP/6001-00000001 (None) Up Playback(demo-congrats) 1 active channel newtonr-laptop*CLI> channel request hangup SIP/6001-00000001 Requested Hangup on channel 'SIP/6001-00000001' [May 2 09:51:19] WARNING[7045][C-00000001]: app_playback.c:493 playback_exec: Playback failed on SIP/6001-00000001 for demo- congrats
11. 11. Asterisk ArchitectureAsterisk Architecture let's take a look at the overall architecture of Asterisk. Asterisk a big program with many components, with complex relationships. To be able to use it, you don't have to know how everything relates in extreme detail. Below is a simplified diagram intended to illustrate the relationships of some major components to each other and to entities outside Asterisk. It is useful to understand how a component may relate to things outside Asterisk as Asterisk is not typically operating without some connectivity or interaction with other network devices or files on the local system.
12. 12. Asterisk Architecture, The Big PictureAsterisk Architecture, The Big Picture
13. 13. Core & ModulesCore & Modules Asterisk has a core that can interact with many modules. Modules called channel drivers provide channels that follow Asterisk dialplan to execute programmed behavior and facilitate communication between devices or programs outside Asterisk. Channels often use bridging infrastructure to interact with other channels. The Core The heart of any Asterisk system is the core. The core loads and builds the dialplan, which is the logic of any Asterisk system. The dialplan contains a list of instructions that Asterisk should follow to know how to handle incoming and outgoing calls on the system.
14. 14. ModulesModules Modules is. From a logistical standpoint, modules are typically files with a .so file extension, which live in the Asterisk modules directory (which is typically /usr/lib/asterisk/modules). When Asterisk starts up, it loads these files and adds their functionality to the system. Asterisk modules which are part of the core have a file name that look like pbx_xxxxx.so.
15. 15. ModulesModules A Few Module Examples chan_pjsip uses res_pjsip and many other res_pjsip modules to provide a SIP stack for SIP devices to interact with Asterisk and with each other through Asterisk. app_voicemail provides traditional PBX-type voicemail features. app_confbridge provides conference bridges with many optional features. res_agi provides the Asterisk Gateway Interface, an API that allows call control from external scripts and programs.
16. 16. Calls and ChannelsCalls and Channels the primary purpose of Asterisk is being an engine for building Real Time Communication systems and applications. In most but not all cases this means you'll deal with the concept of "calls". Calls in telephony terminology typically refer to one phone communicating with (calling) another phone over a medium, such as a PSTN line. However in the case of Asterisk a call typically references one or more channels existing in Asterisk. Here are some example "calls". A phone calling another phone through Asterisk. A phone calling many phones at once through Asterisk. A phone calls an application or the reverse happens. A local channel is created and interacts with an application or another channel. Note that I primarily use phones as an example, however you could refer to any channel or group of channels as a call. It doesn't matter if the devices are phones or something else, like an alarm system sensor or garage door opener.
17. 17. ChannelsChannels Channels are created by Asterisk using Channel Drivers. Channels can be bridged to other channels and be affected by applications and functions.
18. 18. DialplanDialplan Dialplan is the one main method of directing Asterisk behavior. Dialplan exists as text files (for example extensions.conf) . Alternatively dialplan could be read from a database. When writing dialplan, you will make heavy use of applications and functions to affect channels, configuration and features. Dialplan can also call out through other interfaces such as AGI to receive call control instruction from external scripts and programs.
19. 19. Directory and File StructureDirectory and File Structure The top level directories used by Asterisk can be configured in the asterisk.conf configuration file. See /etc/asterisk/asterisk.conf
20. 20. Asterisk Configuration Files astetcdir => /etc/asterisk This location is used to store and read Asterisk configuration files. That is generally files with a .conf extension, but other configuration types as well, for example .lua and .ael.
21. 21. Asterisk ModulesAsterisk Modules astmoddir => /usr/lib/asterisk/modules Loadable modules in Shared Object format (.so) installed by Asterisk or the user should go here.
22. 22. Various LibrariesVarious Libraries astvarlibdir => /var/lib/asterisk Additional library elements and files containing data used in runtime are put here.
23. 23. Database DirectoryDatabase Directory astdbdir => /var/lib/asterisk This location is used to store the data file for Asterisk's internal database. In Asterisk versions using the SQLite3 database, the file will be named astdb.sqlite3. Asterisk use SQLite3 as internal database.
24. 24. Encryption KeysEncryption Keys astkeydir => /var/lib/asterisk When configuring key-based encryption, Asterisk will look in the keys subdirectory of this location for the necessary keys. Ehsan Khoshhal
25. 25. System Data DirectorySystem Data Directory astdatadir => /var/lib/asterisk By default, Asterisk sounds are stored and read from the sounds subdirectory at this location.
26. 26. AGI(Asterisk Gateway Interface)AGI(Asterisk Gateway Interface) DirectoryDirectory astagidir => /var/lib/asterisk/agi-bin When using various AGI applications, Asterisk looks here for the AGI scripts by default.
27. 27. Spool DirectoriesSpool Directories astspooldir => /var/spool/asterisk This directory is used for storing spool files from various core and module- provided components of Asterisk. Most of them use their own subdirectories, such as the following: dictate meetme monitor outgoing recording system tmp Voicemail Ehsan khoshhal, amir tavakoli
28. 28. Running Process DirectoryRunning Process Directory astrundir => /var/run/asterisk When Asterisk is running, you'll see two files here, asterisk.ctl and asterisk.pid. That is the control socket and the PID(Process ID) files for Asterisk. What is the different between /var/run and /proc Ehsan khoshhal, amir tavakoli, masoud bani.
29. 29. Logging OutputLogging Output astlogdir => /var/log/asterisk When Asterisk is configured to provide log file output, it will be stored in this directory.
30. 30. System Binary DirectorySystem Binary Directory astsbindir => /usr/sbin By default, Asterisk looks in this directory for any system binaries that it uses, if you move the Asterisk binary itself or any others that it uses, you'll need to change this location. /usr/sbin mean: Application that compiled from source or installed by user or installed after install system by default placed here. All system default packages and programs placed in /bin and /sbin. /sbin stand for system (or superuser) binaries . App placed in /sbin just run with root or sudoers.
31. 31. aboutabout Email : m.gh@linuxmail.org License : GPLV3 Other project and tutorials: https://github.com/m-gh/ Get latest version of this slides form: https://github.com/m-gh/