Fix faasd CE install script for RHEL-based systems

This change removes the check-update command. This command is not
required and caused the script to exit early if packages are not up to
date.

In addition DNF is now used to install packages. DNF is the successor of
YUM on the latest RHEL-based system.

Signed-off-by: Han Verstraete (OpenFaaS Ltd) <[email protected]>

Author: welteki

hack/install.sh

@@ -47,8 +47,8 @@ verify_system() {
   fi
 }
 
-has_yum() {
-  [ -n "$(command -v yum)" ]
+has_dnf() {
+  [ -n "$(command -v dnf)" ]
 }
 
 has_apt_get() {
@@ -67,14 +67,16 @@ install_required_packages() {
     # reference: https://github.com/openfaas/faasd/pull/237
     $SUDO apt-get update -y
     $SUDO apt-get install -y curl runc bridge-utils iptables
-  elif $(has_yum); then
-    $SUDO yum check-update -y
-    $SUDO yum install -y curl runc iptables-services
+  elif $(has_dnf); then
+    $SUDO dnf install -y \
+      --allowerasing \
+      --setopt=install_weak_deps=False \
+      curl runc iptables-services bridge-utils
   elif $(has_pacman); then
     $SUDO pacman -Syy
     $SUDO pacman -Sy curl runc bridge-utils
   else
-    fatal "Could not find apt-get, yum, or pacman. Cannot install dependencies on this OS."
+    fatal "Could not find apt-get, dnf, or pacman. Cannot install dependencies on this OS."
     exit 1
   fi
 }