prefer cap over setuid for sysetmd-journal in installer (#15741)

netdata-installer.sh

@@ -1239,6 +1239,21 @@ if [ "$(id -u)" -eq 0 ]; then
     fi
   fi
 
+  if [ -f "${NETDATA_PREFIX}/usr/libexec/netdata/plugins.d/systemd-journal.plugin" ]; then
+    run chown "root:${NETDATA_GROUP}" "${NETDATA_PREFIX}/usr/libexec/netdata/plugins.d/systemd-journal.plugin"
+    capabilities=0
+    if ! iscontainer && command -v setcap 1> /dev/null 2>&1; then
+      run chmod 0750 "${NETDATA_PREFIX}/usr/libexec/netdata/plugins.d/systemd-journal.plugin"
+      if run setcap cap_dac_read_search+ep "${NETDATA_PREFIX}/usr/libexec/netdata/plugins.d/systemd-journal.plugin"; then
+        capabilities=1 
+      fi
+    fi
+
+    if [ $capabilities -eq 0 ]; then
+      run chmod 4750 "${NETDATA_PREFIX}/usr/libexec/netdata/plugins.d/systemd-journal.plugin"
+    fi
+  fi
+
   if [ -f "${NETDATA_PREFIX}/usr/libexec/netdata/plugins.d/freeipmi.plugin" ]; then
     run chown "root:${NETDATA_GROUP}" "${NETDATA_PREFIX}/usr/libexec/netdata/plugins.d/freeipmi.plugin"
     run chmod 4750 "${NETDATA_PREFIX}/usr/libexec/netdata/plugins.d/freeipmi.plugin"
@@ -1291,10 +1306,6 @@ if [ "$(id -u)" -eq 0 ]; then
     run chmod 4750 "${NETDATA_PREFIX}/usr/libexec/netdata/plugins.d/local-listeners"
   fi
 
-  if [ -f "${NETDATA_PREFIX}/usr/libexec/netdata/plugins.d/systemd-journal.plugin" ]; then
-    run chown "root:${NETDATA_GROUP}" "${NETDATA_PREFIX}/usr/libexec/netdata/plugins.d/systemd-journal.plugin"
-    run chmod 4750 "${NETDATA_PREFIX}/usr/libexec/netdata/plugins.d/systemd-journal.plugin"
-  fi
 else
   # non-privileged user installation
   run chown "${NETDATA_USER}:${NETDATA_GROUP}" "${NETDATA_LOG_DIR}"