@@ -329,9 +329,6 @@ function _ensure_lsb_release {

         sudo zypper -n install lsb-release

     elif [[ -x $(command -v dnf 2>/dev/null) ]]; then

         sudo dnf install -y redhat-lsb-core

-    elif [[ -x $(command -v yum 2>/dev/null) ]]; then

-        # all rh patforms (fedora, centos, rhel) have this pkg

-        sudo yum install -y redhat-lsb-core

     else

         die $LINENO "Unable to find or auto-install lsb_release"

     fi

@@ -1361,7 +1358,7 @@ function uninstall_package {

     if is_ubuntu; then

         apt_get purge "$@"

     elif is_fedora; then

-        sudo ${YUM:-yum} remove -y "$@" ||:

+        sudo dnf remove -y "$@" ||:

     elif is_suse; then

         sudo zypper remove -y "$@" ||:

     else

@@ -1369,8 +1366,11 @@ function uninstall_package {

     fi

 }

-# Wrapper for ``yum`` to set proxy environment variables

-# Uses globals ``OFFLINE``, ``*_proxy``, ``YUM``

+# Wrapper for ``dnf`` to set proxy environment variables

+# Uses globals ``OFFLINE``, ``*_proxy``

+# The name is kept for backwards compatability with external

+# callers, despite none of our supported platforms using yum

+# any more.

 # yum_install package [package ...]

 function yum_install {

     local result parse_yum_result

@@ -1378,44 +1378,8 @@ function yum_install {

     [[ "$OFFLINE" = "True" ]] && return

     time_start "yum_install"

-

-    # This is a bit tricky, because yum -y assumes missing or failed

-    # packages are OK (see [1]).  We want devstack to stop if we are

-    # installing missing packages.

-    #

-    # Thus we manually match on the output (stack.sh runs in a fixed

-    # locale, so lang shouldn't change).

-    #

-    # If yum returns !0, we echo the result as "YUM_FAILED" and return

-    # that from the awk (we're subverting -e with this trick).

-    # Otherwise we use awk to look for failure strings and return "2"

-    # to indicate a terminal failure.

-    #

-    # [1] https://bugzilla.redhat.com/show_bug.cgi?id=965567

-    parse_yum_result='              \

-        BEGIN { result=0 }          \

-        /^YUM_FAILED/ { result=$2 } \

-        /^No package/ { result=2 }  \

-        /^Failed:/    { result=2 }  \

-        //{ print }                 \

-        END { exit result }'

-    (sudo_with_proxies "${YUM:-yum}" install -y "$@" 2>&1 || echo YUM_FAILED $?) \

-        | awk "$parse_yum_result" && result=$? || result=$?

-

+    sudo_with_proxies dnf install -y "$@"

     time_stop "yum_install"

-

-    # if we return 1, then the wrapper functions will run an update

-    # and try installing the package again as a defense against bad

-    # mirrors.  This can hide failures, especially when we have

-    # packages that are in the "Failed:" section because their rpm

-    # install scripts failed to run correctly (in this case, the

-    # package looks installed, so when the retry happens we just think

-    # the package is OK, and incorrectly continue on).

-    if [ "$result" == 2 ]; then

-        die "Detected fatal package install failure"

-    fi

-

-    return "$result"

 }

 # zypper wrapper to set arguments correctly

@@ -283,19 +283,12 @@ fi

 # to pick up required packages.

 function _install_epel {

-    # NOTE: We always remove and install latest -- some environments

-    # use snapshot images, and if EPEL version updates they break

-    # unless we update them to latest version.

-    if sudo yum repolist enabled epel | grep -q 'epel'; then

-        uninstall_package epel-release || true

-    fi

-

     # epel-release is in extras repo which is enabled by default

     install_package epel-release

     # RDO repos are not tested with epel and may have incompatibilities so

     # let's limit the packages fetched from epel to the ones not in RDO repos.

-    sudo yum-config-manager --save --setopt=includepkgs=debootstrap,dpkg epel

+    sudo dnf config-manager --save --setopt=includepkgs=debootstrap,dpkg epel

 }

 function _install_rdo {

@@ -813,15 +813,6 @@ SERVICE_GRACEFUL_SHUTDOWN_TIMEOUT=${SERVICE_GRACEFUL_SHUTDOWN_TIMEOUT:-5}

 # Service graceful shutdown timeout

 WORKER_TIMEOUT=${WORKER_TIMEOUT:-90}

-# Choose DNF on RedHat/Fedora platforms with it, or otherwise default

-# to YUM.  Can remove this when only dnf is supported (i.e. centos7

-# disappears)

-if [[ -e /usr/bin/dnf ]]; then

-    YUM=${YUM:-dnf}

-else

-    YUM=${YUM:-yum}

-fi

-

 # Common Configuration

 # --------------------