simple to install elasticsearch

elasticsearch-install.sh

#!/bin/bash
#elasticsearch 8.2.0
#test only centos7
ES_DOWNLOAD_URL=https://artifacts.elastic.co/downloads/elasticsearch/elasticsearch-8.2.0-linux-x86_64.tar.gz
ES_INSTALL_DIR=/usr/local/elasticsearch
ES_TMP_DIR=/tmp/elasticsearch
REQUIRED_SOFTWARE_LIST=(wget tar sed)
#perl-Digest-SHA 
function check_software() {
    check_software_bool $1
    if [ $? == 1 ]; then
        echo "${1} installed"
    else
        echo "${1} not installed"
        echo "start to install ${1}"
        yum install $1 -y
    fi
}

function check_software_bool() {
    RESULT=`whereis $1`
    RESULT_LENGTH=`echo -n $RESULT | wc -c`
    PACK_LENGTH=`echo -n $1 | wc -c`
    PACK_LENGTH=`expr $PACK_LENGTH + 1`
    if [ $RESULT_LENGTH -gt $PACK_LENGTH ]; then
        return 1
    else
        return 0
    fi
}

function required_software_check() {
    yum update -y
    for i in "${REQUIRED_SOFTWARE_LIST[@]}"
    do
        check_software $i
    done
}

function check_error() {
    if [ $? -ne 0 ];then
        echo $1
        remove
        exit 1
    fi
}

function install() {
    required_software_check
    mkdir $ES_TMP_DIR
    mkdir ${ES_INSTALL_DIR}
    groupadd elasticsearch
    useradd -r -s /bin/false -g elasticsearch elasticsearch
    SOURCE_PWD=`pwd`
    cd $ES_TMP_DIR
    wget -O elasticsearch.tar.gz $ES_DOWNLOAD_URL
    check_error "downlaod elasticsearch.tar.gz failed!"
    # wget -O elasticsearch.tar.gz.sha512 https://artifacts.elastic.co/downloads/elasticsearch/elasticsearch-${ES_VERSION}-linux-x86_64.tar.gz.sha512
    # shasum -a 512 -c elasticsearch.tar.gz.sha512 
    tar -xzf elasticsearch.tar.gz --strip-components 1 -C ${ES_INSTALL_DIR}
    check_error "decompression elasticsearch.tar.gz failed!"
    chown -R elasticsearch:elasticsearch $ES_INSTALL_DIR
    chmod -R 750 $ES_INSTALL_DIR
    cat << EOT > /etc/systemd/system/elasticsearch.service
[Unit]
Description=elasticsearch

Wants=network.target
After=syslog.target network-online.target

[Service]
User=elasticsearch
Type=simple
Environment=GOGC=20
ExecStart=${ES_INSTALL_DIR}/bin/elasticsearch
Restart=on-failure
RestartSec=10
KillMode=process
LimitNOFILE=65536

[Install]
WantedBy=multi-user.target
EOT
    systemctl enable --now elasticsearch
    check_error "start service failed!"
    cd $SOURCE_PWD
    rm -rf ${ES_TMP_DIR}
    result=`${ES_INSTALL_DIR}/bin/elasticsearch-reset-password`
    echo $result
    clear
    echo "install finished!"
    echo "use ${ES_INSTALL_DIR}/bin/elasticsearch-reset-password -u elastic to get password!"
}

function remove() {
    systemctl stop elasticsearch
    systemctl disable elasticsearch
    rm -rf /etc/systemd/system/elasticsearch.service
    rm -rf $ES_INSTALL_DIR
    userdel elasticsearch
    groupdel elasticsearch
    clear
    echo "remove finished!"
}

function help() {
    cat << EOF
    elasticsearch install helper!!!
    usage: 
    ./elasticsearch.sh menu
    install: install elasticsearch
    remove: remove elasticsearch
EOF
}

function main() {
    if [ $# -lt 1 ]; then
        help
    else
        case $1 in
            install)
                install
            ;;
            remove)
                remove
            ;;
            *)
                echo 'command not found!'
                help
            ;;
        esac
    fi
    exit 0
}

main $@