Update supported versions for Fedora: 23, 24, and 25.

The bootstrap script should match the supported versions of SaltStack
more closely, and we don't support versions that are considered EOL by
the OS distributors themselves.

This change updates the bootstrap script to support Fedora 23, 24, and 25.

Since "dnf" replaced "yum" as the package provider in Fedora 23, we no
longer need to set the $FEDORA_PACKAGE_MANAGER variable based on the
version of Fedora. This can simply be "dnf" now for Fedora installs.

README.rst

@@ -200,7 +200,7 @@ Supported Operating Systems
 .. note::
 
   Bootstrap may fail to install Salt on the cutting-edge version of distributions with frequent
-  release cycle, such as: Amazon Linux, Fedora, openSUSE Tumbleweed or Ubuntu non-LTS. Check the
+  release cycles such as: Amazon Linux, Fedora, openSUSE Tumbleweed, or Ubuntu non-LTS. Check the
   versions from the list below. Also, see the `Unsupported Distro`_ and
   `Adding Support for Other Operating Systems`_ sections.
 
@@ -231,7 +231,7 @@ Red Hat family
 
 - Amazon Linux 2012.09/2013.03/2013.09/2014.03/2014.09
 - CentOS 5/6/7
-- Fedora 17/18/20/21/22
+- Fedora 23/24/25
 - Oracle Linux 5/6/7
 - Red Hat Enterprise Linux 5/6/7
 - Scientific Linux 5/6/7

bootstrap-salt.sh

@@ -1744,7 +1744,7 @@ __check_end_of_life_versions() {
 
         fedora)
             # Fedora lower than 18 are no longer supported
-            if [ "$DISTRO_MAJOR_VERSION" -lt 18 ]; then
+            if [ "$DISTRO_MAJOR_VERSION" -lt 23 ]; then
                 echoerror "End of life distributions are not supported."
                 echoerror "Please consider upgrading to the next stable. See:"
                 echoerror "    https://fedoraproject.org/wiki/Releases"
@@ -3225,16 +3225,7 @@ install_debian_check_services() {
 #   Fedora Install Functions
 #
 
-FEDORA_PACKAGE_MANAGER="yum"
-
-__fedora_get_package_manager() {
-  if [ "$DISTRO_MAJOR_VERSION" -ge 22 ] || __check_command_exists dnf; then
-    FEDORA_PACKAGE_MANAGER="dnf"
-  fi
-}
-
 install_fedora_deps() {
-    __fedora_get_package_manager
 
     if [ $_DISABLE_REPOS -eq $BS_FALSE ]; then
         if [ "$_ENABLE_EXTERNAL_ZMQ_REPOS" -eq $BS_TRUE ]; then
@@ -3244,32 +3235,25 @@ install_fedora_deps() {
         __install_saltstack_copr_salt_repository || return 1
     fi
 
-    __PACKAGES="yum-utils PyYAML libyaml python-crypto python-jinja2 python-zmq"
-
-    if [ "$DISTRO_MAJOR_VERSION" -ge 23 ]; then
-        __PACKAGES="${__PACKAGES} python2-msgpack python2-requests"
-    else
-        __PACKAGES="${__PACKAGES} python-msgpack python-requests"
-    fi
+    __PACKAGES="yum-utils PyYAML libyaml python-crypto python-jinja2 python-zmq python2-msgpack python2-requests"
 
     # shellcheck disable=SC2086
-    $FEDORA_PACKAGE_MANAGER install -y ${__PACKAGES} || return 1
+    dnf install -y ${__PACKAGES} || return 1
 
     if [ "$_UPGRADE_SYS" -eq $BS_TRUE ]; then
-        $FEDORA_PACKAGE_MANAGER -y update || return 1
+        dnf -y update || return 1
     fi
 
     if [ "${_EXTRA_PACKAGES}" != "" ]; then
         echoinfo "Installing the following extra packages as requested: ${_EXTRA_PACKAGES}"
         # shellcheck disable=SC2086
-        $FEDORA_PACKAGE_MANAGER install -y ${_EXTRA_PACKAGES} || return 1
+        dnf install -y ${_EXTRA_PACKAGES} || return 1
     fi
 
     return 0
 }
 
 install_fedora_stable() {
-    __fedora_get_package_manager
     __PACKAGES=""
 
     if [ "$_INSTALL_CLOUD" -eq $BS_TRUE ];then
@@ -3286,7 +3270,7 @@ install_fedora_stable() {
     fi
 
     # shellcheck disable=SC2086
-    $FEDORA_PACKAGE_MANAGER install -y ${__PACKAGES} || return 1
+    dnf install -y ${__PACKAGES} || return 1
 
     return 0
 }
@@ -3308,16 +3292,15 @@ install_fedora_stable_post() {
 }
 
 install_fedora_git_deps() {
-    __fedora_get_package_manager
 
     if [ "$_INSECURE_DL" -eq $BS_FALSE ] && [ "${_SALT_REPO_URL%%://*}" = "https" ]; then
-        $FEDORA_PACKAGE_MANAGER ca-certificates || return 1
+        dnf ca-certificates || return 1
     fi
 
     install_fedora_deps || return 1
 
     if ! __check_command_exists git; then
-        $FEDORA_PACKAGE_MANAGER install -y git || return 1
+       dnf install -y git || return 1
     fi
 
     __git_clone_and_checkout || return 1
@@ -3345,7 +3328,7 @@ install_fedora_git_deps() {
     fi
 
     # shellcheck disable=SC2086
-    $FEDORA_PACKAGE_MANAGER install -y ${__PACKAGES} || return 1
+    dnf install -y ${__PACKAGES} || return 1
 
     if [ "${__PIP_PACKAGES}" != "" ]; then
         # shellcheck disable=SC2086,SC2090