doc/: don't mention CentOS

It's EOL.

doc/02-installation.md

@@ -83,21 +83,6 @@ apt update
 ```
 <!-- {% endif %} -->
 
-<!-- {% if centos %} -->
-### CentOS Repository <a id="centos-repository"></a>
-
-```bash
-wget https://packages.icinga.com/centos/ICINGA-release.repo -O /etc/yum.repos.d/ICINGA-release.repo
-```
-
-The packages for CentOS depend on other packages which are distributed
-as part of the [EPEL repository](https://fedoraproject.org/wiki/EPEL):
-
-```bash
-yum install epel-release
-```
-<!-- {% endif %} -->
-
 <!-- {% if rhel %} -->
 ### RHEL Repository <a id="rhel-repository"></a>
 
@@ -223,7 +208,7 @@ You can install Icinga 2 by using your distribution's package manager
 to install the `icinga2` package. The following commands must be executed
 with `root` permissions unless noted otherwise.
 
-<!-- {% if centos or rhel or fedora or amazon_linux %} -->
+<!-- {% if rhel or fedora or amazon_linux %} -->
 !!! tip
 
     If you have [SELinux](22-selinux.md) enabled, the package `icinga2-selinux` is also required.
@@ -238,21 +223,6 @@ apt install icinga2
 ```
 <!-- {% endif %} -->
 
-<!-- {% if centos %} -->
-<!-- {% if not icingaDocs %} -->
-#### CentOS
-<!-- {% endif %} -->
-!!! info
-
-    Note that installing Icinga 2 is only supported on CentOS 7 as CentOS 8 is EOL.
-
-```bash
-yum install icinga2
-systemctl enable icinga2
-systemctl start icinga2
-```
-<!-- {% endif %} -->
-
 <!-- {% if rhel %} -->
 #### RHEL 8 or Later
 
@@ -350,17 +320,6 @@ apt install monitoring-plugins
 ```
 <!-- {% endif %} -->
 
-<!-- {% if centos %} -->
-<!-- {% if not icingaDocs %} -->
-#### CentOS
-<!-- {% endif %} -->
-The packages for CentOS depend on other packages which are distributed as part of the EPEL repository.
-
-```bash
-yum install nagios-plugins-all
-```
-<!-- {% endif %} -->
-
 <!-- {% if rhel %} -->
 <!-- {% if not icingaDocs %} -->
 #### RHEL
@@ -448,7 +407,7 @@ Restart Icinga 2 for these changes to take effect.
 systemctl restart icinga2
 ```
 
-<!-- {% if amazon_linux or centos or debian or rhel or sles or ubuntu %} -->
+<!-- {% if amazon_linux or debian or rhel or sles or ubuntu %} -->
 ## Set up Icinga DB <a id="set-up-icinga-db"></a>
 
 Icinga DB is a set of components for publishing, synchronizing and
@@ -500,20 +459,6 @@ yum install icingadb-redis
 ```
 <!-- {% endif %} -->
 
-<!-- {% if centos %} -->
-<!-- {% if not icingaDocs %} -->
-##### CentOS
-<!-- {% endif %} -->
-
-!!! info
-
-    Note that installing Icinga DB Redis is only supported on CentOS 7 as CentOS 8 is EOL.
-
-```bash
-yum install icingadb-redis
-```
-<!-- {% endif %} -->
-
 <!-- {% if debian or ubuntu %} -->
 <!-- {% if not icingaDocs %} -->
 ##### Debian / Ubuntu
@@ -627,9 +572,6 @@ you have completed the instructions here and can proceed to
 <!-- {% if amazon_linux %} -->
 [install the Icinga DB daemon on Amazon Linux](https://icinga.com/docs/icinga-db/latest/doc/02-Installation/01-Amazon-Linux/#installing-icinga-db-package),
 <!-- {% endif %} -->
-<!-- {% if centos %} -->
-[install the Icinga DB daemon on CentOS](https://icinga.com/docs/icinga-db/latest/doc/02-Installation/02-CentOS/#installing-icinga-db-package),
-<!-- {% endif %} -->
 <!-- {% if debian %} -->
 [install the Icinga DB daemon on Debian](https://icinga.com/docs/icinga-db/latest/doc/02-Installation/03-Debian/#installing-icinga-db-package),
 <!-- {% endif %} -->

doc/03-monitoring-basics.md

@@ -2729,7 +2729,7 @@ Requirements:
 * Icinga 2 as client on the remote node
 * icinga user with sudo permissions to the httpd daemon
 
-Example on CentOS 7:
+Example on RHEL:
 
 ```
 # visudo

doc/05-service-monitoring.md

@@ -51,7 +51,7 @@ described. Try running the plugin after setup and [ensure it works](05-service-m
 Prior to using the check plugin with Icinga 2 you should ensure that it is working properly
 by trying to run it on the console using whichever user Icinga 2 is running as:
 
-RHEL/CentOS/Fedora
+RHEL/Fedora
 
 ```bash
 sudo -u icinga /usr/lib64/nagios/plugins/check_mysql_health --help
@@ -111,7 +111,7 @@ Can't locate Net/SNMP.pm in @INC (you may need to install the Net::SNMP module)
 
 Prior to installing the Perl module via CPAN, look for a distribution
 specific package, e.g. `libnet-snmp-perl` on Debian/Ubuntu or `perl-Net-SNMP`
-on RHEL/CentOS.
+on RHEL.
 
 
 #### Optional: Custom Path <a id="service-monitoring-plugins-custom-path"></a>

doc/06-distributed-monitoring.md

@@ -264,7 +264,7 @@ The setup wizard will ensure that the following steps are taken:
 * Update the [ApiListener](06-distributed-monitoring.md#distributed-monitoring-apilistener) and [constants](04-configuration.md#constants-conf) configuration.
 * Update the [icinga2.conf](04-configuration.md#icinga2-conf) to disable the `conf.d` inclusion, and add the `api-users.conf` file inclusion.
 
-Here is an example of a master setup for the `icinga2-master1.localdomain` node on CentOS 7:
+Here is an example of a master setup for the `icinga2-master1.localdomain` node:
 
 ```
 [[email protected] /]# icinga2 node wizard
@@ -1031,9 +1031,7 @@ in `/etc/icinga2/icinga2.conf`.
 > Defaults to disabled.
 
 Now it is time to validate the configuration and to restart the Icinga 2 daemon
-on both nodes.
-
-Example on CentOS 7:
+on both nodes:
 
 ```
 [[email protected] /]# icinga2 daemon -C
@@ -1112,7 +1110,8 @@ Save the changes and validate the configuration on the master node:
 ```
 [[email protected] /]# icinga2 daemon -C
 ```
-Restart the Icinga 2 daemon (example for CentOS 7):
+
+Restart the Icinga 2 daemon:
 
 ```
 [[email protected] /]# systemctl restart icinga2
@@ -1221,9 +1220,7 @@ object ApiListener "api" {
 ```
 
 Now it is time to validate the configuration and to restart the Icinga 2 daemon
-on both nodes.
-
-Example on CentOS 7:
+on both nodes:
 
 ```
 [[email protected] /]# icinga2 daemon -C
@@ -1285,7 +1282,7 @@ Save the changes and validate the configuration on the master node:
 [[email protected] /]# icinga2 daemon -C
 ```
 
-Restart the Icinga 2 daemon (example for CentOS 7):
+Restart the Icinga 2 daemon:
 
 ```
 [[email protected] /]# systemctl restart icinga2

doc/11-cli-commands.md

@@ -73,7 +73,7 @@ RPM and Debian packages install the bash completion files into
 
 You need to install the `bash-completion` package if not already installed.
 
-RHEL/CentOS/Fedora:
+RHEL/Fedora:
 
 ```bash
 yum install bash-completion

doc/14-features.md

@@ -815,16 +815,6 @@ apt-get install icinga2-ido-mysql
     default. You can skip the automated setup and install/upgrade the
     database manually if you prefer.
 
-###### CentOS 7
-
-!!! info
-
-    Note that installing `icinga2-ido-mysql` is only supported on CentOS 7 as CentOS 8 is EOL.
-
-```bash
-yum install icinga2-ido-mysql
-```
-
 ###### RHEL 8
 
 ```bash
@@ -914,16 +904,6 @@ apt-get install icinga2-ido-pgsql
     You can skip the automated setup and install/upgrade the database manually
     if you prefer that.
 
-###### CentOS 7
-
-!!! info
-
-    Note that installing `icinga2-ido-pgsql` is only supported on CentOS 7 as CentOS 8 is EOL.
-
-```bash
-yum install icinga2-ido-pgsql
-```
-
 ###### RHEL 8
 
 ```bash

doc/21-development.md

@@ -48,7 +48,7 @@ or `icinga2-ido-mysql`.
 Distribution       | Command
 -------------------|------------------------------------------
 Debian/Ubuntu      | `apt-get install icinga2-dbg`
-RHEL/CentOS        | `yum install icinga2-debuginfo`
+RHEL               | `yum install icinga2-debuginfo`
 Fedora             | `dnf install icinga2-debuginfo icinga2-bin-debuginfo icinga2-ido-mysql-debuginfo`
 SLES/openSUSE      | `zypper install icinga2-bin-debuginfo icinga2-ido-mysql-debuginfo`
 
@@ -65,7 +65,7 @@ Install GDB in your development environment.
 Distribution       | Command
 -------------------|------------------------------------------
 Debian/Ubuntu      | `apt-get install gdb`
-RHEL/CentOS        | `yum install gdb`
+RHEL               | `yum install gdb`
 Fedora             | `dnf install gdb`
 SLES/openSUSE      | `zypper install gdb`
 
@@ -537,7 +537,7 @@ packages.
 If you encounter a problem, please [open a new issue](https://github.com/Icinga/icinga2/issues/new/choose)
 on GitHub and mention that you're testing the snapshot packages.
 
-#### RHEL/CentOS <a id="development-tests-snapshot-packages-rhel"></a>
+#### RHEL <a id="development-tests-snapshot-packages-rhel"></a>
 
 2.11+ requires the EPEL repository for Boost 1.66+.
 
@@ -1332,9 +1332,6 @@ autocmd BufWinLeave * call clearmatches()
 
 ### Linux Dev Environment <a id="development-linux-dev-env"></a>
 
-Based on CentOS 7, we have an early draft available inside the Icinga Vagrant boxes:
-[centos7-dev](https://github.com/Icinga/icinga-vagrant/tree/master/centos7-dev).
-
 If you're compiling Icinga 2 natively without any virtualization layer in between,
 this usually is faster. This is also the reason why developers on macOS prefer native builds
 over Linux or Windows VMs. Don't forget to test the actual code on Linux later! Socket specific
@@ -1357,21 +1354,20 @@ mkdir -p release debug
 Proceed with the specific distribution examples below. Keep in mind that these instructions
 are best effort and sometimes out-of-date. Git Master may contain updates.
 
-* [CentOS 7](21-development.md#development-linux-dev-env-centos)
+* [Fedora 40](21-development.md#development-linux-dev-env-fedora)
 * [Debian 10 Buster](21-development.md#development-linux-dev-env-debian)
 * [Ubuntu 18 Bionic](21-development.md#development-linux-dev-env-ubuntu)
 
-
-#### CentOS 7 <a id="development-linux-dev-env-centos"></a>
+#### Fedora 40 <a id="development-linux-dev-env-fedora"></a>
 
 ```bash
-yum -y install gdb vim git bash-completion htop centos-release-scl
+yum -y install gdb vim git bash-completion htop
 
 yum -y install rpmdevtools ccache \
- cmake make devtoolset-11-gcc-c++ flex bison \
- openssl-devel boost169-devel systemd-devel \
+ cmake make gcc-c++ flex bison \
+ openssl-devel boost-devel systemd-devel \
  mysql-devel postgresql-devel libedit-devel \
- devtoolset-11-libstdc++-devel
+ libstdc++-devel
 
 groupadd icinga
 groupadd icingacmd
@@ -1389,10 +1385,10 @@ slower but allows for better debugging insights.
 For benchmarks, change `CMAKE_BUILD_TYPE` to `RelWithDebInfo` and
 build inside the `release` directory.
 
-First, off export some generics for Boost.
+First, off export a workaround for Boost.
 
 ```bash
-export I2_BOOST="-DBoost_NO_BOOST_CMAKE=TRUE -DBoost_NO_SYSTEM_PATHS=TRUE -DBOOST_LIBRARYDIR=/usr/lib64/boost169 -DBOOST_INCLUDEDIR=/usr/include/boost169 -DBoost_ADDITIONAL_VERSIONS='1.69;1.69.0'"
+export I2_BOOST="-DBoost_NO_BOOST_CMAKE=TRUE"
 ```
 
 Second, add the prefix path to it.
@@ -1412,8 +1408,8 @@ Fourth, depending on your likings, you may add a bash alias for building,
 or invoke the commands inside:
 
 ```bash
-alias i2_debug="cd /root/icinga2; mkdir -p debug; cd debug; scl enable devtoolset-11 -- cmake $I2_DEBUG ..; make -j2; sudo make -j2 install; cd .."
-alias i2_release="cd /root/icinga2; mkdir -p release; cd release; scl enable devtoolset-11 -- cmake $I2_RELEASE ..; make -j2; sudo make -j2 install; cd .."
+alias i2_debug="cd /root/icinga2; mkdir -p debug; cd debug; cmake $I2_DEBUG ..; make -j2; sudo make -j2 install; cd .."
+alias i2_release="cd /root/icinga2; mkdir -p release; cd release; cmake $I2_RELEASE ..; make -j2; sudo make -j2 install; cd .."
 ```
 
 This is taken from the [centos7-dev](https://github.com/Icinga/icinga-vagrant/tree/master/centos7-dev) Vagrant box.
@@ -1429,7 +1425,7 @@ chown -R icinga:icinga /usr/local/icinga2/var/
 /usr/local/icinga2/sbin/icinga2 api setup
 vim /usr/local/icinga2/etc/icinga2/conf.d/api-users.conf
 
-/usr/local/icinga2/lib/icinga2/sbin/icinga2 daemon
+/usr/local/icinga2/lib64/icinga2/sbin/icinga2 daemon
 ```
 
 #### Debian 10 <a id="development-linux-dev-env-debian"></a>
@@ -2203,7 +2199,7 @@ Icinga application using a dist tarball (including notes for distributions):
     * Debian/Ubuntu: libpq-dev
     * postgresql-dev on Alpine
 * libedit (CLI console)
-    * RHEL/Fedora: libedit-devel on CentOS (RHEL requires rhel-7-server-optional-rpms)
+    * RHEL/Fedora: libedit-devel (RHEL requires rhel-7-server-optional-rpms)
     * Debian/Ubuntu/Alpine: libedit-dev
 * Termcap (only required if libedit doesn't already link against termcap/ncurses)
     * RHEL/Fedora: libtermcap-devel
@@ -2351,7 +2347,7 @@ can be used to disable the usage of `git describe`.
 
 ### Building RPMs <a id="development-package-builds-rpms"></a>
 
-#### Build Environment on RHEL, CentOS, Fedora, Amazon Linux
+#### Build Environment on RHEL, Fedora, Amazon Linux
 
 Setup your build environment:
 
@@ -2407,7 +2403,7 @@ spectool -g ../SPECS/icinga2.spec
 cd $HOME/rpmbuild
 ```
 
-Install the build dependencies. Example for CentOS 7:
+Install the build dependencies:
 
 ```bash
 yum -y install libedit-devel ncurses-devel gcc-c++ libstdc++-devel openssl-devel \
@@ -2436,21 +2432,9 @@ rpmbuild -ba SPECS/icinga2.spec
 The following packages are required to build the SELinux policy module:
 
 * checkpolicy
-* selinux-policy (selinux-policy on CentOS 6, selinux-policy-devel on CentOS 7)
+* selinux-policy-devel
 * selinux-policy-doc
 
-##### RHEL/CentOS 7
-
-The RedHat Developer Toolset is required for building Icinga 2 beforehand.
-This contains a C++ compiler which supports C++17 features.
-
-```bash
-yum install centos-release-scl
-```
-
-Dependencies to devtools-11 are used in the RPM SPEC, so the correct tools
-should be used for building.
-
 ##### Amazon Linux
 
 If you prefer to build packages offline, a suitable Vagrant box is located

lib/base/utility.cpp

@@ -1664,7 +1664,7 @@ static bool ReleaseHelper(String *platformName, String *platformVersion)
 		}
 	}
 
-	/* Centos/RHEL < 7 */
+	/* RHEL < 7 */
 	release.close();
 	release.open("/etc/redhat-release");
 	if (release.is_open()) {