AmazonLinux2 amazon-linux-extrasでPHPをインストール

Amazon マシンイメージ (AMI)：Amazon Linux 2 AMI (HVM), SSD Volume Type - ami-e99f4896

extras-libraryでインストール可能なリストは下記コマンドで確認できます。

# amazon-linux-extras
  0  ansible2                 available  [ =2.4.2 ]
  1  emacs                    available  [ =25.3 ]
  2  memcached1.5             available  [ =1.5.1 ]
  3  nginx1.12                available  [ =1.12.2 ]
  4  postgresql9.6            available  [ =9.6.6  =9.6.8 ]
  5  postgresql10             available  [ =10 ]
  6  python3                  available  [ =3.6.2 ]
  7  redis4.0                 available  [ =4.0.5  =4.0.10 ]
  8  R3.4                     available  [ =3.4.3 ]
  9  rust1                    available  \
        [ =1.22.1  =1.26.0  =1.26.1 ]
 10  vim                      available  [ =8.0 ]
 11  golang1.9                available  [ =1.9.2 ]
 12  ruby2.4                  available  [ =2.4.2  =2.4.4 ]
 13  nano                     available  [ =2.9.1 ]
 14  php7.2                   available  [ =7.2.0  =7.2.4  =7.2.5 ]
 15  lamp-mariadb10.2-php7.2  available  \
        [ =10.2.10_7.2.0  =10.2.10_7.2.4  =10.2.10_7.2.5 ]
 16  libreoffice              available  [ =5.0.6.2_15 ]
 17  gimp                     available  [ =2.8.22 ]
 18  docker=latest            enabled    [ =17.12.1  =18.03.1 ]
 19  mate-desktop1.x          available  [ =1.19.0  =1.20.0 ]
 20  GraphicsMagick1.3        available  [ =1.3.29 ]
 21  tomcat8.5                available  [ =8.5.31 ]

php7.2があることが確認できます。
Extras Library ではソフトウェアをトピックと呼ぶらしいです。
php7.2に紐づくトピックを下記コマンドで確認します。

# amazon-linux-extras info php7.2
php7.2 recommends php-cli                    # yum install php-cli
php7.2 recommends php-pdo                    # yum install php-pdo
php7.2 recommends php-fpm                    # yum install php-fpm
php7.2 recommends php-json                   # yum install php-json
php7.2 recommends php-mysqlnd                # yum install php-mysqlnd

トピックのインストールは下記コマンドで実行可能です

amazon-linux-extras install php7.2


インストール:
  php-cli.x86_64 0:7.2.5-3.amzn2.0.2            php-fpm.x86_64 0:7.2.5-3.amzn2.0.2        php-json.x86_64 0:7.2.5-3.amzn2.0.2       
  php-mysqlnd.x86_64 0:7.2.5-3.amzn2.0.2        php-pdo.x86_64 0:7.2.5-3.amzn2.0.2       

依存性関連をインストールしました:
  php-common.x86_64 0:7.2.5-3.amzn2.0.2                                                                                               

完了しました!
  0  ansible2                 available  [ =2.4.2 ]
  1  emacs                    available  [ =25.3 ]
  2  memcached1.5             available  [ =1.5.1 ]
  3  nginx1.12                available  [ =1.12.2 ]
  4  postgresql9.6            available  [ =9.6.6  =9.6.8 ]
  5  postgresql10             available  [ =10 ]
  6  python3                  available  [ =3.6.2 ]
  7  redis4.0                 available  [ =4.0.5  =4.0.10 ]
  8  R3.4                     available  [ =3.4.3 ]
  9  rust1                    available  \
        [ =1.22.1  =1.26.0  =1.26.1 ]
 10  vim                      available  [ =8.0 ]
 11  golang1.9                available  [ =1.9.2 ]
 12  ruby2.4                  available  [ =2.4.2  =2.4.4 ]
 13  nano                     available  [ =2.9.1 ]
 14  php7.2=latest            enabled    [ =7.2.0  =7.2.4  =7.2.5 ]
 15  lamp-mariadb10.2-php7.2  available  \
        [ =10.2.10_7.2.0  =10.2.10_7.2.4  =10.2.10_7.2.5 ]
 16  libreoffice              available  [ =5.0.6.2_15 ]
 17  gimp                     available  [ =2.8.22 ]
 18  docker=latest            enabled    [ =17.12.1  =18.03.1 ]
 19  mate-desktop1.x          available  [ =1.19.0  =1.20.0 ]
 20  GraphicsMagick1.3        available  [ =1.3.29 ]
 21  tomcat8.5                available  [ =8.5.31 ]

インストールされたphpのバージョンを確認

 php -v
PHP 7.2.5 (cli) (built: May 29 2018 19:08:12) ( NTS )
Copyright (c) 1997-2018 The PHP Group
Zend Engine v3.2.0, Copyright (c) 1998-2018 Zend Technologies