Adding upstream version 2.14.2.upstream/2.14.2upstream

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

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+# Icinga 2 CLI Commands <a id="cli-commands"></a>
+
+Icinga 2 comes with a number of CLI commands which support bash autocompletion.
+
+These CLI commands will allow you to use certain functionality
+provided by and around Icinga 2.
+
+Each CLI command provides its own help and usage information, so please
+make sure to always run them with the `--help` parameter.
+
+Run `icinga2` without any arguments to get a list of all available global
+options.
+
+```
+# icinga2
+icinga2 - The Icinga 2 network monitoring daemon (version: v2.11.0)
+
+Usage:
+  icinga2 <command> [<arguments>]
+
+Supported commands:
+  * api setup (setup for API)
+  * ca list (lists all certificate signing requests)
+  * ca restore (restores a removed certificate request)
+  * ca remove (removes an outstanding certificate request)  
+  * ca sign (signs an outstanding certificate request)
+  * console (Icinga debug console)
+  * daemon (starts Icinga 2)
+  * feature disable (disables specified feature)
+  * feature enable (enables specified feature)
+  * feature list (lists all available features)
+  * node setup (set up node)
+  * node wizard (wizard for node setup)
+  * object list (lists all objects)
+  * pki new-ca (sets up a new CA)
+  * pki new-cert (creates a new CSR)
+  * pki request (requests a certificate)
+  * pki save-cert (saves another Icinga 2 instance's certificate)
+  * pki sign-csr (signs a CSR)
+  * pki ticket (generates a ticket)
+  * pki verify (verify TLS certificates: CN, signed by CA, is CA; Print certificate)
+  * variable get (gets a variable)
+  * variable list (lists all variables)
+
+Global options:
+  -h [ --help ]             show this help message
+  -V [ --version ]          show version information
+  --color                   use VT100 color codes even when stdout is not a
+                            terminal
+  -D [ --define ] arg       define a constant
+  -a [ --app ] arg          application library name (default: icinga)
+  -l [ --library ] arg      load a library
+  -I [ --include ] arg      add include search directory
+  -x [ --log-level ] arg    specify the log level for the console log.
+                            The valid value is either debug, notice,
+                            information (default), warning, or critical
+  -X [ --script-debugger ]  whether to enable the script debugger
+
+Report bugs at <https://github.com/Icinga/icinga2>
+Icinga home page: <https://icinga.com/>
+```
+
+
+## Icinga 2 CLI Bash Autocompletion <a id="cli-commands-autocompletion"></a>
+
+Bash Auto-Completion (pressing `<TAB>`) is provided only for the corresponding context.
+
+While `--config` suggests and auto-completes files and directories on disk,
+`feature enable` only suggests disabled features.
+
+RPM and Debian packages install the bash completion files into
+`/etc/bash_completion.d/icinga2`.
+
+You need to install the `bash-completion` package if not already installed.
+
+RHEL/CentOS/Fedora:
+
+```bash
+yum install bash-completion
+```
+
+SUSE:
+
+```bash
+zypper install bash-completion
+```
+
+Debian/Ubuntu:
+
+```bash
+apt-get install bash-completion
+```
+
+Ensure that the `bash-completion.d` directory is added to your shell
+environment. You can manually source the icinga2 bash-completion file
+into your current session and test it:
+
+```bash
+source /etc/bash-completion.d/icinga2
+```
+
+
+## Icinga 2 CLI Global Options <a id="cli-commands-global-options"></a>
+
+### Application Type
+
+By default the `icinga2` binary loads the `icinga` library. A different application type
+can be specified with the `--app` command-line option.
+Note: This is not needed by the average Icinga user, only developers.
+
+### Libraries
+
+Instead of loading libraries using the [`library` config directive](17-language-reference.md#library)
+you can also use the `--library` command-line option.
+Note: This is not needed by the average Icinga user, only developers.
+
+### Constants
+
+[Global constants](17-language-reference.md#constants) can be set using the `--define` command-line option.
+
+### Config Include Path <a id="config-include-path"></a>
+
+When including files you can specify that the include search path should be
+checked. You can do this by putting your configuration file name in angle
+brackets like this:
+
+```
+include <test.conf>
+```
+
+This causes Icinga 2 to search its include path for the configuration file
+`test.conf`. By default the installation path for the [Icinga Template Library](10-icinga-template-library.md#icinga-template-library)
+is the only search directory.
+
+Using the `--include` command-line option additional search directories can be
+added.
+
+## CLI command: Api <a id="cli-command-api"></a>
+
+Provides helper functions to enable and setup the
+[Icinga 2 API](12-icinga2-api.md#icinga2-api-setup).
+
+### CLI command: Api Setup <a id="cli-command-api-setup "></a>
+
+```
+# icinga2 api setup --help
+icinga2 - The Icinga 2 network monitoring daemon (version: v2.11.0)
+
+Usage:
+  icinga2 api setup [<arguments>]
+
+Setup for Icinga 2 API.
+
+Global options:
+  -h [ --help ]             show this help message
+  -V [ --version ]          show version information
+  --color                   use VT100 color codes even when stdout is not a
+                            terminal
+  -D [ --define ] arg       define a constant
+  -I [ --include ] arg      add include search directory
+  -x [ --log-level ] arg    specify the log level for the console log.
+                            The valid value is either debug, notice,
+                            information (default), warning, or critical
+  -X [ --script-debugger ]  whether to enable the script debugger
+
+Command options:
+  --cn arg                  The certificate's common name
+
+Report bugs at <https://github.com/Icinga/icinga2>
+Get support: <https://icinga.com/support/>
+Documentation: <https://icinga.com/docs/>
+Icinga home page: <https://icinga.com/>
+```
+
+## CLI command: Ca <a id="cli-command-ca"></a>
+
+List and manage incoming certificate signing requests. More details
+can be found in the [signing methods](06-distributed-monitoring.md#distributed-monitoring-setup-sign-certificates-master)
+chapter. This CLI command is available since v2.8.
+
+```
+# icinga2 ca --help
+icinga2 - The Icinga 2 network monitoring daemon (version: v2.11.0)
+
+Usage:
+  icinga2 <command> [<arguments>]
+
+Supported commands:
+  * ca list (lists all certificate signing requests)
+  * ca sign (signs an outstanding certificate request)
+  * ca restore (restores a removed certificate request)
+  * ca remove (removes an outstanding certificate request)
+
+Global options:
+  -h [ --help ]             show this help message
+  -V [ --version ]          show version information
+  --color                   use VT100 color codes even when stdout is not a
+                            terminal
+  -D [ --define ] arg       define a constant
+  -a [ --app ] arg          application library name (default: icinga)
+  -l [ --library ] arg      load a library
+  -I [ --include ] arg      add include search directory
+  -x [ --log-level ] arg    specify the log level for the console log.
+                            The valid value is either debug, notice,
+                            information (default), warning, or critical
+  -X [ --script-debugger ]  whether to enable the script debugger
+
+Report bugs at <https://github.com/Icinga/icinga2>
+Icinga home page: <https://icinga.com/>
+```
+
+
+### CLI command: Ca List <a id="cli-command-ca-list"></a>
+
+```
+icinga2 ca list --help
+icinga2 - The Icinga 2 network monitoring daemon (version: v2.11.0)
+
+Usage:
+  icinga2 ca list [<arguments>]
+
+Lists pending certificate signing requests.
+
+Global options:
+  -h [ --help ]             show this help message
+  -V [ --version ]          show version information
+  --color                   use VT100 color codes even when stdout is not a
+                            terminal
+  -D [ --define ] arg       define a constant
+  -I [ --include ] arg      add include search directory
+  -x [ --log-level ] arg    specify the log level for the console log.
+                            The valid value is either debug, notice,
+                            information (default), warning, or critical
+  -X [ --script-debugger ]  whether to enable the script debugger
+
+Command options:
+  --all                     List all certificate signing requests, including
+                            signed. Note: Old requests are automatically
+                            cleaned by Icinga after 1 week.
+  --removed                 List all removed CSRs (for use with 'ca restore')
+  --json                    encode output as JSON
+
+Report bugs at <https://github.com/Icinga/icinga2>
+Get support: <https://icinga.com/support/>
+Documentation: <https://icinga.com/docs/>
+Icinga home page: <https://icinga.com/>
+```
+
+## CLI command: Console <a id="cli-command-console"></a>
+
+The CLI command `console` can be used to debug and evaluate Icinga 2 config expressions,
+e.g. to test [functions](17-language-reference.md#functions) in your local sandbox.
+
+```
+$ icinga2 console
+Icinga 2 (version: v2.11.0)
+<1> => function test(name) {
+<1> ..   log("Hello " + name)
+<1> .. }
+null
+<2> => test("World")
+information/config: Hello World
+null
+<3> =>
+```
+
+Further usage examples can be found in the [library reference](18-library-reference.md#library-reference) chapter.
+
+```
+# icinga2 console --help
+icinga2 - The Icinga 2 network monitoring daemon (version: v2.11.0)
+
+Usage:
+  icinga2 console [<arguments>]
+
+Interprets Icinga script expressions.
+
+Global options:
+  -h [ --help ]             show this help message
+  -V [ --version ]          show version information
+  --color                   use VT100 color codes even when stdout is not a
+                            terminal
+  -D [ --define ] arg       define a constant
+  -a [ --app ] arg          application library name (default: icinga)
+  -l [ --library ] arg      load a library
+  -I [ --include ] arg      add include search directory
+  -x [ --log-level ] arg    specify the log level for the console log.
+                            The valid value is either debug, notice,
+                            information (default), warning, or critical
+  -X [ --script-debugger ]  whether to enable the script debugger
+
+Command options:
+  -c [ --connect ] arg      connect to an Icinga 2 instance
+  -e [ --eval ] arg         evaluate expression and terminate
+  -r [ --file ] arg         evaluate a file and terminate
+  --syntax-only             only validate syntax (requires --eval or --file)
+  --sandbox                 enable sandbox mode
+
+Report bugs at <https://github.com/Icinga/icinga2>
+Icinga home page: <https://icinga.com/>
+```
+
+
+On operating systems without the `libedit` library installed there is no
+support for line-editing or a command history. However you can
+use the `rlwrap` program if you require those features:
+
+```bash
+rlwrap icinga2 console
+```
+
+The debug console can be used to connect to a running Icinga 2 instance using
+the [REST API](12-icinga2-api.md#icinga2-api). [API permissions](12-icinga2-api.md#icinga2-api-permissions)
+are required for executing config expressions and auto-completion.
+
+> **Note**
+>
+> The debug console does not currently support TLS certificate verification.
+>
+> Runtime modifications are not validated and might cause the Icinga 2
+> daemon to crash or behave in an unexpected way. Use these runtime changes
+> at your own risk and rather *inspect and debug objects read-only*.
+
+You can specify the API URL using the `--connect` parameter.
+
+Although the password can be specified there process arguments on UNIX platforms are
+usually visible to other users (e.g. through `ps`). In order to securely specify the
+user credentials the debug console supports two environment variables:
+
+  Environment variable | Description
+  ---------------------|-------------
+  ICINGA2_API_USERNAME | The API username.
+  ICINGA2_API_PASSWORD | The API password.
+
+Here's an example:
+
+```
+$ ICINGA2_API_PASSWORD=icinga icinga2 console --connect 'https://root@localhost:5665/'
+Icinga 2 (version: v2.11.0)
+<1> =>
+```
+
+Once connected you can inspect variables and execute other expressions by entering them at the prompt:
+
+```
+<1> => var h = get_host("icinga2-agent1.localdomain")
+null
+<2> => h.last_check_result
+{
+        active = true
+        check_source = "icinga2-agent1.localdomain"
+        command = [ "/usr/local/sbin/check_ping", "-H", "127.0.0.1", "-c", "5000,100%", "-w", "3000,80%" ]
+        execution_end = 1446653527.174983
+        execution_start = 1446653523.152673
+        exit_status = 0.000000
+        output = "PING OK - Packet loss = 0%, RTA = 0.11 ms"
+        performance_data = [ "rta=0.114000ms;3000.000000;5000.000000;0.000000", "pl=0%;80;100;0" ]
+        schedule_end = 1446653527.175133
+        schedule_start = 1446653583.150000
+        state = 0.000000
+        type = "CheckResult"
+        vars_after = {
+                attempt = 1.000000
+                reachable = true
+                state = 0.000000
+                state_type = 1.000000
+        }
+        vars_before = {
+                attempt = 1.000000
+                reachable = true
+                state = 0.000000
+                state_type = 1.000000
+        }
+}
+<3> =>
+```
+
+You can use the `--eval` parameter to evaluate a single expression in batch mode.
+Using the `--file` option you can specify a file which should be evaluated.
+The output format for batch mode is JSON.
+
+The `--syntax-only` option can be used in combination with `--eval` or `--file`
+to check a script for syntax errors. In this mode the script is parsed to identify
+syntax errors but not evaluated.
+
+Here's an example that retrieves the command that was used by Icinga to check the `icinga2-agent1.localdomain` host:
+
+```
+$ ICINGA2_API_PASSWORD=icinga icinga2 console --connect 'https://root@localhost:5665/' --eval 'get_host("icinga2-agent1.localdomain").last_check_result.command' | python -m json.tool
+[
+    "/usr/local/sbin/check_ping",
+    "-H",
+    "127.0.0.1",
+    "-c",
+    "5000,100%",
+    "-w",
+    "3000,80%"
+]
+```
+
+## CLI command: Daemon <a id="cli-command-daemon"></a>
+
+The CLI command `daemon` provides the functionality to start/stop Icinga 2.
+Furthermore it allows to run the [configuration validation](11-cli-commands.md#config-validation).
+
+```
+# icinga2 daemon --help
+icinga2 - The Icinga 2 network monitoring daemon (version: v2.11.0)
+
+Usage:
+  icinga2 daemon [<arguments>]
+
+Starts Icinga 2.
+
+Global options:
+  -h [ --help ]             show this help message
+  -V [ --version ]          show version information
+  --color                   use VT100 color codes even when stdout is not a
+                            terminal
+  -D [ --define ] arg       define a constant
+  -a [ --app ] arg          application library name (default: icinga)
+  -l [ --library ] arg      load a library
+  -I [ --include ] arg      add include search directory
+  -x [ --log-level ] arg    specify the log level for the console log.
+                            The valid value is either debug, notice,
+                            information (default), warning, or critical
+  -X [ --script-debugger ]  whether to enable the script debugger
+
+Command options:
+  -c [ --config ] arg       parse a configuration file
+  -z [ --no-config ]        start without a configuration file
+  -C [ --validate ]         exit after validating the configuration
+  --dump-objects            write icinga2.debug cache file for icinga2 object list
+  -e [ --errorlog ] arg     log fatal errors to the specified log file (only
+                            works in combination with --daemonize or
+                            --close-stdio)
+  -d [ --daemonize ]        detach from the controlling terminal
+  --close-stdio             do not log to stdout (or stderr) after startup
+
+Report bugs at <https://github.com/Icinga/icinga2>
+Icinga home page: <https://icinga.com/>
+```
+
+### Config Files <a id="cli-command-daemon-config-files"></a>
+
+You can specify one or more configuration files with the `--config` option.
+Configuration files are processed in the order they're specified on the command-line.
+
+When no configuration file is specified and the `--no-config` is not used
+Icinga 2 automatically falls back to using the configuration file
+`ConfigDir + "/icinga2.conf"` (where ConfigDir is usually `/etc/icinga2`).
+
+### Validation <a id="cli-command-daemon-validation"></a>
+
+The `--validate` option can be used to check if configuration files
+contain errors. If any errors are found, the exit status is 1, otherwise 0
+is returned. More details in the [configuration validation](11-cli-commands.md#config-validation) chapter.
+
+## CLI command: Feature <a id="cli-command-feature"></a>
+
+The `feature enable` and `feature disable` commands can be used to enable and disable features:
+
+```
+# icinga2 feature disable <tab>
+--app              --define           --include          --log-level        --version          checker            graphite           mainlog
+--color            --help             --library          --script-debugger  api                command            ido-mysql          notification
+```
+
+```
+# icinga2 feature enable <tab>
+--app              --define           --include          --log-level        --version          debuglog           ido-pgsql          livestatus         perfdata           syslog
+--color            --help             --library          --script-debugger  compatlog          gelf               influxdb           opentsdb           statusdata
+```
+
+The `feature list` command shows which features are currently enabled:
+
+```
+# icinga2 feature list
+Disabled features: compatlog debuglog gelf ido-pgsql influxdb livestatus opentsdb perfdata statusdata syslog
+Enabled features: api checker command graphite ido-mysql mainlog notification
+```
+
+## CLI command: Node <a id="cli-command-node"></a>
+
+Provides the functionality to setup master and client
+nodes in a [distributed monitoring](06-distributed-monitoring.md#distributed-monitoring) scenario.
+
+```
+# icinga2 node --help
+icinga2 - The Icinga 2 network monitoring daemon (version: v2.11.0)
+
+Usage:
+  icinga2 <command> [<arguments>]
+
+Supported commands:
+  * node setup (set up node)
+  * node wizard (wizard for node setup)
+
+Global options:
+  -h [ --help ]             show this help message
+  -V [ --version ]          show version information
+  --color                   use VT100 color codes even when stdout is not a
+                            terminal
+  -D [ --define ] arg       define a constant
+  -a [ --app ] arg          application library name (default: icinga)
+  -l [ --library ] arg      load a library
+  -I [ --include ] arg      add include search directory
+  -x [ --log-level ] arg    specify the log level for the console log.
+                            The valid value is either debug, notice,
+                            information (default), warning, or critical
+  -X [ --script-debugger ]  whether to enable the script debugger
+
+Report bugs at <https://github.com/Icinga/icinga2>
+Icinga home page: <https://icinga.com/>
+```
+
+## CLI command: Object <a id="cli-command-object"></a>
+
+The `object` CLI command can be used to list all configuration objects and their
+attributes. The command also shows where each of the attributes was modified and as such
+provides debug information for further configuration problem analysis.
+That way you can also identify which objects have been created from your [apply rules](17-language-reference.md#apply).
+
+Configuration modifications are not immediately updated. Furthermore there is a known issue with
+[group assign expressions](17-language-reference.md#group-assign) which are not reflected in the host object output.
+You need to run `icinga2 daemon -C --dump-objects` in order to update the `icinga2.debug` cache file.
+
+More information can be found in the [troubleshooting](15-troubleshooting.md#troubleshooting-list-configuration-objects) section.
+
+```
+# icinga2 object --help
+icinga2 - The Icinga 2 network monitoring daemon (version: v2.11.0)
+
+Usage:
+  icinga2 <command> [<arguments>]
+
+Supported commands:
+  * object list (lists all objects)
+
+Global options:
+  -h [ --help ]             show this help message
+  -V [ --version ]          show version information
+  --color                   use VT100 color codes even when stdout is not a
+                            terminal
+  -D [ --define ] arg       define a constant
+  -a [ --app ] arg          application library name (default: icinga)
+  -l [ --library ] arg      load a library
+  -I [ --include ] arg      add include search directory
+  -x [ --log-level ] arg    specify the log level for the console log.
+                            The valid value is either debug, notice,
+                            information (default), warning, or critical
+  -X [ --script-debugger ]  whether to enable the script debugger
+
+Report bugs at <https://github.com/Icinga/icinga2>
+Icinga home page: <https://icinga.com/>
+```
+
+## CLI command: Pki <a id="cli-command-pki"></a>
+
+Provides the CLI commands to
+
+* generate a new certificate authority (CA)
+* generate a new CSR or self-signed certificate
+* sign a CSR and return a certificate
+* save a master certificate manually
+* request a signed certificate from the master
+* generate a new ticket for the client setup
+
+This functionality is used by the [node setup/wizard](11-cli-commands.md#cli-command-node) CLI commands.
+You will need them in the [distributed monitoring chapter](06-distributed-monitoring.md#distributed-monitoring).
+
+```
+# icinga2 pki --help
+icinga2 - The Icinga 2 network monitoring daemon (version: v2.12.0)
+
+Usage:
+  icinga2 <command> [<arguments>]
+
+Supported commands:
+  * pki new-ca (sets up a new CA)
+  * pki new-cert (creates a new CSR)
+  * pki request (requests a certificate)
+  * pki save-cert (saves another Icinga 2 instance's certificate)
+  * pki sign-csr (signs a CSR)
+  * pki ticket (generates a ticket)
+  * pki verify (verify TLS certificates: CN, signed by CA, is CA; Print certificate)
+
+Global options:
+  -h [ --help ]             show this help message
+  -V [ --version ]          show version information
+  --color                   use VT100 color codes even when stdout is not a
+                            terminal
+  -D [ --define ] arg       define a constant
+  -a [ --app ] arg          application library name (default: icinga)
+  -l [ --library ] arg      load a library
+  -I [ --include ] arg      add include search directory
+  -x [ --log-level ] arg    specify the log level for the console log.
+                            The valid value is either debug, notice,
+                            information (default), warning, or critical
+  -X [ --script-debugger ]  whether to enable the script debugger
+
+Report bugs at <https://github.com/Icinga/icinga2>
+Icinga home page: <https://icinga.com/>
+```
+
+## CLI command: Variable <a id="cli-command-variable"></a>
+
+Lists all configured variables (constants) in a similar fashion like [object list](11-cli-commands.md#cli-command-object).
+
+```
+# icinga2 variable --help
+icinga2 - The Icinga 2 network monitoring daemon (version: v2.11.0)
+
+Usage:
+  icinga2 <command> [<arguments>]
+
+Supported commands:
+  * variable get (gets a variable)
+  * variable list (lists all variables)
+
+Global options:
+  -h [ --help ]             show this help message
+  -V [ --version ]          show version information
+  --color                   use VT100 color codes even when stdout is not a
+                            terminal
+  -D [ --define ] arg       define a constant
+  -a [ --app ] arg          application library name (default: icinga)
+  -l [ --library ] arg      load a library
+  -I [ --include ] arg      add include search directory
+  -x [ --log-level ] arg    specify the log level for the console log.
+                            The valid value is either debug, notice,
+                            information (default), warning, or critical
+  -X [ --script-debugger ]  whether to enable the script debugger
+
+Report bugs at <https://github.com/Icinga/icinga2>
+Icinga home page: <https://icinga.com/>
+```
+
+## Enabling/Disabling Features <a id="enable-features"></a>
+
+Icinga 2 provides configuration files for some commonly used features. These
+are installed in the `/etc/icinga2/features-available` directory and can be
+enabled and disabled using the `icinga2 feature enable` and `icinga2 feature disable`
+[CLI commands](11-cli-commands.md#cli-command-feature), respectively.
+
+The `icinga2 feature enable` CLI command creates symlinks in the
+`/etc/icinga2/features-enabled` directory which is included by default
+in the example configuration file.
+
+You can view a list of enabled and disabled features:
+
+```
+# icinga2 feature list
+Disabled features: api command compatlog debuglog graphite icingastatus ido-mysql ido-pgsql livestatus notification perfdata statusdata syslog
+Enabled features: checker mainlog notification
+```
+
+Using the `icinga2 feature enable` command you can enable features:
+
+```
+# icinga2 feature enable graphite
+Enabling feature graphite. Make sure to restart Icinga 2 for these changes to take effect.
+```
+
+You can disable features using the `icinga2 feature disable` command:
+
+```
+# icinga2 feature disable ido-mysql livestatus
+Disabling feature ido-mysql. Make sure to restart Icinga 2 for these changes to take effect.
+Disabling feature livestatus. Make sure to restart Icinga 2 for these changes to take effect.
+```
+
+The `icinga2 feature enable` and `icinga2 feature disable` commands do not
+restart Icinga 2. You will need to restart Icinga 2 using the init script
+after enabling or disabling features.
+
+
+
+## Configuration Validation <a id="config-validation"></a>
+
+Once you've edited the configuration files make sure to tell Icinga 2 to validate
+the configuration changes. Icinga 2 will log any configuration error including
+a hint on the file, the line number and the affected configuration line itself.
+
+The following example creates an apply rule without any `assign` condition.
+
+```
+apply Service "my-ping4" {
+  import "generic-service"
+  check_command = "ping4"
+  //assign where host.address
+}
+```
+
+Validate the configuration:
+
+```
+# icinga2 daemon -C
+
+[2014-05-22 17:07:25 +0200] critical/ConfigItem: Location:
+/etc/icinga2/conf.d/tests/my.conf(5): }
+/etc/icinga2/conf.d/tests/my.conf(6):
+/etc/icinga2/conf.d/tests/my.conf(7): apply Service "my-ping4" {
+                                        ^^^^^^^^^^^^^
+/etc/icinga2/conf.d/tests/my.conf(8):   import "test-generic-service"
+/etc/icinga2/conf.d/tests/my.conf(9):   check_command = "ping4"
+
+Config error: 'apply' is missing 'assign'
+[2014-05-22 17:07:25 +0200] critical/ConfigItem: 1 errors, 0 warnings.
+Icinga 2 detected configuration errors.
+```
+
+If you encounter errors during configuration validation, please make sure
+to read the [troubleshooting](15-troubleshooting.md#troubleshooting) chapter.
+
+You can also use the [CLI command](11-cli-commands.md#cli-command-object) `icinga2 object list`
+after validation passes to analyze object attributes, inheritance or created
+objects by apply rules.
+Find more on troubleshooting with `object list` in [this chapter](15-troubleshooting.md#troubleshooting-list-configuration-objects).
+
+
+## Reload on Configuration Changes <a id="config-change-reload"></a>
+
+Every time you have changed your configuration you should first tell Icinga 2
+to [validate](11-cli-commands.md#config-validation). If there are no validation errors, you can
+safely reload the Icinga 2 daemon.
+
+```bash
+systemctl reload icinga2
+```
+
+The `reload` action will send the `SIGHUP` signal to the Icinga 2 daemon
+which will validate the configuration in a separate process and not stop
+the other events like check execution, notifications, etc.