Merge 'Drop CentOS7 specific codes' from Takuya ASADA

Since we decided to drop CentOS7 support from latest version of Scylla, now we can drop CentOS7 specific codes from packaging scripts and setup scripts.

Related scylladb/scylla-enterprise#3502

Closes scylladb/scylladb#16365

* github.com:scylladb/scylladb:
  scylla-server.service: switch deprecated PermissionsStartsOnly to ExecStartPre=+
  dist: drop legacy control group parameters
  scylla-server.slice: Drop workaround for MemorySwapMax=0 bug
  dist: move AmbientCapabilities to scylla-server.service
  Revert "scylla_setup: add warning for CentOS7 default kernel"

[avi: CentOS 7 reached EOL on June 2024]

dist/common/scripts/scylla_setup

@@ -15,7 +15,6 @@ import shutil
 import io
 import stat
 import distro
-import platform
 from scylla_util import *
 from subprocess import run, DEVNULL
 
@@ -171,9 +170,6 @@ def warn_offline(setup):
 def warn_offline_missing_pkg(setup, pkg):
     colorprint('{red}{setup} disabled by default, since {pkg} not available.{nocolor}', setup=setup, pkg=pkg)
 
-def is_rhel7_old_kernel():
-    return is_redhat_variant() and distro.major_version() == '7' and platform.release().startswith('3.10')
-
 if __name__ == '__main__':
     if not is_nonroot() and os.getuid() > 0:
         print('Requires root permission.')
@@ -332,14 +328,6 @@ if __name__ == '__main__':
         return when_interactive_ask_service(interactive, msg1, msg2, default)
 
     if not is_nonroot():
-        if is_rhel7_old_kernel():
-            colorprint('{red}RHEL/CentOS7 default kernel detected.{nocolor}')
-            colorprint('{red}To get optimal performance, please install kernel-ml kernel.{nocolor}')
-            continue_setup = interactive_ask_service('Do you want to continue the setup with current kernel?', 'Yes - continue the setup, No - abort the setup.', True)
-            if not continue_setup:
-                colorprint('{red}Setup aborted.{nocolor}')
-                sys.exit(1)
-
         kernel_check = interactive_ask_service('Do you want to run check your kernel version?', 'Yes - runs a  script to verify that the kernel for this instance qualifies to run Scylla. No - skips the kernel check.', kernel_check)
         args.no_kernel_check = not kernel_check
         if kernel_check:

dist/common/systemd/scylla-helper.slice

@@ -15,10 +15,3 @@ MemoryHigh=4%
 # MemoryMax is the OOM point. As Scylla reserves 7% by default, the other two percent goes to
 # the kernel and other non contained processes
 MemoryMax=5%
-# Systemd deprecated settings BlockIOWeight, MemoryLimit and CPUShares. But they are still the ones used in RHEL7
-# Newer SystemD wants MemoryHigh/MemoryMax, IOWeight and CPUWeight instead. Luckily both newer and older SystemD seem to
-# ignore the unwanted option so safest to get both. Using just the old versions would work too but
-# seems less future proof. Using just the new versions does not work at all for RHEL7/
-MemoryLimit=5%
-CPUShares=10
-BlockIOWeight=10

dist/common/systemd/scylla-server.service

@@ -7,7 +7,6 @@ Wants=scylla-housekeeping-daily.timer
 Conflicts=abrt-ccpp.service
 
 [Service]
-PermissionsStartOnly=true
 Type=notify
 LimitCORE=infinity
 LimitMEMLOCK=infinity
@@ -16,9 +15,9 @@ LimitAS=infinity
 LimitNPROC=8096
 EnvironmentFile=/etc/sysconfig/scylla-server
 EnvironmentFile=/etc/scylla.d/*.conf
-ExecStartPre=/opt/scylladb/scripts/scylla_prepare
+ExecStartPre=+/opt/scylladb/scripts/scylla_prepare
 ExecStart=/usr/bin/scylla $SCYLLA_ARGS $SEASTAR_IO $DEV_MODE $CPUSET $MEM_CONF
-ExecStopPost=/opt/scylladb/scripts/scylla_stop
+ExecStopPost=+/opt/scylladb/scripts/scylla_stop
 TimeoutStartSec=1y
 TimeoutStopSec=900
 KillMode=process
@@ -26,6 +25,7 @@ Restart=on-abnormal
 User=scylla
 OOMScoreAdjust=-950
 SyslogLevelPrefix=false
+AmbientCapabilities=CAP_SYS_NICE CAP_IPC_LOCK
 Slice=scylla-server.slice
 
 [Install]

dist/common/systemd/scylla-server.slice

@@ -12,8 +12,7 @@ CPUAccounting=true
 # seems less future proof. Using just the new versions does not work at all for RHEL7/
 BlockIOWeight=1000
 IOWeight=1000
-# Should be zero, but work around https://github.com/systemd/systemd/issues/8363 for older systemd
-MemorySwapMax=1
+MemorySwapMax=0
 CPUShares=1000
 CPUWeight=1000
 

scylla_post_install.sh

@@ -18,34 +18,16 @@ version_ge() {
 # Install capabilities.conf when AmbientCapabilities supported
 . /etc/os-release
 
-# the command below will still work in systems without systemctl (like docker) and across all
-# versions of systemd. We will set the version to 0 if systemctl is not found and then be able
-# to use that in tests.
-SYSTEMD_VER=$(( systemctl --version 2>/dev/null || echo 0 0) | head -n1 | awk '{print $2}')
-RHEL=$(echo $ID $ID_LIKE | grep -oi rhel)
-SYSTEMD_REL=0
-if [ "$RHEL" ]; then
-    SYSTEMD_REL=`rpm -q systemd --qf %{release}|sed -n "s/\([0-9]*\).*/\1/p"`
-fi
-
-AMB_SUPPORT=`grep -c ^CapAmb: /proc/self/status`
-
 KERNEL_VER=$(uname -r)
 
-# AmbientCapabilities supported from v229 but it backported to v219-33 on RHEL7
-if [ $SYSTEMD_VER -ge 229 ] || [[ $SYSTEMD_VER -eq 219 && $SYSTEMD_REL -ge 33 ]]; then
-    if [ $AMB_SUPPORT -eq 1 ]; then
-        AMB_CAPABILITIES="CAP_SYS_NICE CAP_IPC_LOCK"
-        # CAP_PERFMON is only available on linux-5.8+
-        if version_ge $KERNEL_VER 5.8; then
-            AMB_CAPABILITIES="$AMB_CAPABILITIES CAP_PERFMON"
-        fi
-        mkdir -p /etc/systemd/system/scylla-server.service.d/
-        cat << EOS > /etc/systemd/system/scylla-server.service.d/capabilities.conf
+# CAP_PERFMON is only available on linux-5.8+
+if version_ge $KERNEL_VER 5.8; then
+    AMB_CAPABILITIES="$AMB_CAPABILITIES CAP_PERFMON"
+    mkdir -p /etc/systemd/system/scylla-server.service.d/
+    cat << EOS > /etc/systemd/system/scylla-server.service.d/capabilities.conf
 [Service]
-AmbientCapabilities=$AMB_CAPABILITIES
+AmbientCapabilities=CAP_PERFMON
 EOS
-    fi
 fi
 
 # For systems with not a lot of memory, override default reservations for the slices
@@ -59,18 +41,6 @@ if [ $MEMTOTAL_BYTES -lt 23008753371 ]; then
 [Slice]
 MemoryHigh=1200M
 MemoryMax=1400M
-MemoryLimit=1400M
-EOS
-
-# On CentOS7, systemd does not support percentage-based parameter.
-# To apply memory parameter on CentOS7, we need to override the parameter
-# in bytes, instead of percentage.
-elif [ "$RHEL" -a "$VERSION_ID" = "7" ]; then
-    MEMORY_LIMIT=$((MEMTOTAL_BYTES / 100 * 5))
-    mkdir -p /etc/systemd/system/scylla-helper.slice.d/
-    cat << EOS > /etc/systemd/system/scylla-helper.slice.d/memory.conf
-[Slice]
-MemoryLimit=$MEMORY_LIMIT
 EOS
 fi