add entrypoint to dockerfile and doc

fix resource usage

entrypoint.sh

@@ -0,0 +1,77 @@
+#!/bin/bash
+
+VERBOSE=false
+while getopts "v" arg; do
+  case $arg in
+    v )
+      VERBOSE=true
+    ;;
+    * )
+    ;;
+  esac
+done
+
+# Сдвигаем позиционные параметры после обработки опций
+shift $((OPTIND-1))
+JAR_FILE_NAME=$1
+
+if [ -f /sys/fs/cgroup/memory/memory.limit_in_bytes ]
+then
+  LIMITED_RAM_CONTAINER_CGROUP_SIZE_BYTES=$(cat /sys/fs/cgroup/memory/memory.limit_in_bytes)
+  if [ $VERBOSE = true ]; then echo "Cgroups v1 are used"; fi
+
+elif [ -f /sys/fs/cgroup/memory.max ]
+then
+  LIMITED_RAM_CONTAINER_CGROUP_SIZE_BYTES=$(cat /sys/fs/cgroup/memory.max)
+  if [ $VERBOSE = true ]; then echo "Cgroups v2 are used"; fi
+else
+  echo "No cgroups files with memory limits"; exit 1
+fi
+
+#
+LIMITED_RAM_CONTAINER_CGROUP_SIZE_MB=$((LIMITED_RAM_CONTAINER_CGROUP_SIZE_BYTES / 1024 / 1024))
+TOMCAT_THREADS_MAX=${TOMCAT_THREADS_MAX:-100}
+TOMCAT_THREADS_MIN=${TOMCAT_THREADS_MIN-$TOMCAT_THREADS_MAX}
+HIKARI_DB_MAXIMUM_POOL_SIZE=${HIKARI_DB_MAXIMUM_POOL_SIZE:-10}
+HIKARI_DB_MINIMUM_IDLE_SIZE=${HIKARI_DB_MINIMUM_IDLE_SIZE:-$HIKARI_DB_MAXIMUM_POOL_SIZE}
+JVM_NATIVE_MB=${JVM_NATIVE_MB:-120}
+STOCK_SIZE_MB=$((TOMCAT_THREADS_MAX / 2 + HIKARI_DB_MAXIMUM_POOL_SIZE + JVM_NATIVE_MB))
+LIMITED_MAXRAM_JAVA_SIZE_MB=$((LIMITED_RAM_CONTAINER_CGROUP_SIZE_MB - STOCK_SIZE_MB))
+#
+RESERVED_CODE_CACHE_SIZE_MB=${RESERVED_CODE_CACHE_SIZE_MB:-64}
+MAX_METASPACE_SIZE_MB=${MAX_METASPACE_SIZE_MB:-80}
+DIRECT_BYTES_BUFFERS_MB=${DIRECT_BYTES_BUFFERS_MB:-10}
+COMPRESSED_CLASS_SPACE_MB=${COMPRESSED_CLASS_SPACE_MB:-16}
+NON_HEAP_SIZE_MB=$((RESERVED_CODE_CACHE_SIZE_MB + MAX_METASPACE_SIZE_MB + DIRECT_BYTES_BUFFERS_MB + COMPRESSED_CLASS_SPACE_MB))
+#
+HEAP_GC_SIZE_MB=$((LIMITED_MAXRAM_JAVA_SIZE_MB - NON_HEAP_SIZE_MB))
+OVERHEAD_GC_SIZE_PERCENT=${OVERHEAD_GC_SIZE_PERCENT:-5}
+OVERHEAD_GC_SIZE_MB=$((HEAP_GC_SIZE_MB * OVERHEAD_GC_SIZE_PERCENT / 100))
+HEAP_SIZE_MB=$((HEAP_GC_SIZE_MB - OVERHEAD_GC_SIZE_MB))
+#
+MAX_RAM_PERCENTAGE=$((HEAP_SIZE_MB * 100 / LIMITED_MAXRAM_JAVA_SIZE_MB))
+
+# export calculated environments
+export TOMCAT_THREADS_MAX=$TOMCAT_THREADS_MAX
+export TOMCAT_THREADS_MIN=$TOMCAT_THREADS_MIN
+export HIKARI_DB_MAXIMUM_POOL_SIZE=$HIKARI_DB_MAXIMUM_POOL_SIZE
+export HIKARI_DB_MINIMUM_IDLE_SIZE=$HIKARI_DB_MINIMUM_IDLE_SIZE
+
+if [ $VERBOSE = true ]
+then
+  echo "LIMITED_MAXRAM_JAVA_SIZE_MB=$LIMITED_MAXRAM_JAVA_SIZE_MB"
+  echo "HEAP_SIZE_MB=$HEAP_SIZE_MB"
+  echo "MAX_RAM_PERCENTAGE=$MAX_RAM_PERCENTAGE"
+fi
+
+# shellcheck disable=SC2086
+exec java \
+  -XX:+UseContainerSupport \
+  -XX:+ExitOnOutOfMemoryError \
+  -XX:MaxRAM="${LIMITED_MAXRAM_JAVA_SIZE_MB}m" \
+  -XX:MaxRAMPercentage="$MAX_RAM_PERCENTAGE" \
+  -XX:+SegmentedCodeCache \
+  -XX:ReservedCodeCacheSize="${RESERVED_CODE_CACHE_SIZE_MB}m" \
+  -XX:MaxMetaspaceSize="${MAX_METASPACE_SIZE_MB}m" \
+  $JAVA_OPTS_OVERRIDE \
+  -jar /app/"$JAR_FILE_NAME"