Aah right, I find those commands tricky when I search on google because we have docker container and the configuration is slightly different. I am still struggling to find out how I can see actual indexes and data via command line. I my Indices directory in Elasticsearch there are no actual names of the indices as I see on UI.
root@ansible:/usr/local/bin# curl -X GET http://172.17.0.3:9200/_cat/indices?pretty
green open gl-failures_70 0-SMsbiWT6m6Q2grl9TIHQ 2 0 0 0 416b 416b
green open gl-failures_75 j5Y5f5erQ0iGX-h7dicIBg 2 0 0 0 416b 416b
green open gl-failures_73 wh6246BFQ4yux-chCC9Ymw 2 0 0 0 416b 416b
green open gl-failures_74 VhB-jShSTXC8dv4p7LMvGw 2 0 0 0 416b 416b
green open gl-failures_71 5EKaiLQXRLyvmy6O76Wz4Q 2 0 0 0 416b 416b
green open gl-failures_72 WxKsOTrKSWKGGoBtvWrGTw 2 0 0 0 416b 416b
green open graylog_36 CK1_UbhzReOX0dghZlV_7A 2 0 185797 0 41.3mb 41.3mb
green open graylog_35 cllJF1T3SwqW98yMqVk9WQ 2 0 48446 0 10.8mb 10.8mb
green open graylog_38 -JGlAUEwS9-A1aoOb0sh7w 2 0 68243 0 15mb 15mb
green open graylog_37 Rn18l_FnSn6FfceXrbOyOA 2 0 31678 0 7.4mb 7.4mb
green open graylog_39 KkZ9VZCCRbumKVCqppGznQ 2 0 25717 0 6.2mb 6.2mb
green open gl-failures_48 UghG8pQvRx6H-dw-Wm4rcg 2 0 0 0 416b 416b
green open gl-failures_49 q34y6mSxQECOvgnIorHWGA 2 0 0 0 416b 416b
green open gl-failures_46 BhgAbE2zSJqijClizpkiwA 2 0 0 0 416b 416b
green open gl-failures_47 BbA1C3OdRTWv23bTaI4kuQ 2 0 0 0 416b 416b
green open graylog_41 ozcGKVcXQee3GjNbWMgwiA 2 0 26166 0 6.2mb 6.2mb
green open graylog_40 mmypHdvLTQOk0M2HvJ5rqA 2 0 25717 0 6.1mb 6.1mb
green open graylog_43 KdJ_a7XQRcajre-Cc2We7w 2 0 26110 0 6.2mb 6.2mb
green open graylog_42 tABeMuBiQJCjgF2Txdq3EA 2 0 26550 0 6.4mb 6.4mb
green open graylog_45 AhwS4kmsSHSREgxONiWNKg 2 0 36629 0 8.6mb 8.6mb
green open graylog_44 APRfXxe7R5uPv-6_QvTHWw 2 0 26820 0 6.4mb 6.4mb
green open graylog_47 0Pid3PlaRlqhoPqbE9y7WQ 2 0 25629 0 6.1mb 6.1mb
green open graylog_46 Rua1xuHHSMyOQCKnpO6h3Q 2 0 25852 0 6.2mb 6.2mb
green open graylog_49 lec3ySJRS2-uYprQ4F1s8Q 2 0 4183 0 2.3mb 2.3mb
green open graylog_48 6fJCSHQxSSeIIs-6Ec5PZA 2 0 25607 0 6.1mb 6.1mb
green open gl-failures_55 icjSVuhaQUeeP5ElnR6Ttg 2 0 0 0 416b 416b
green open gl-failures_56 er1KZddsTmyhbbnNJkJ8nA 2 0 0 0 416b 416b
green open gl-failures_53 qKOL72pOSo6zTK_6dy-G7Q 2 0 0 0 416b 416b
green open gl-failures_54 ferZIwrhStGayYCUH7_R6w 2 0 0 0 416b 416b
green open gl-failures_51 KPEIeAVgQAiKu0MTo2HX4w 2 0 0 0 416b 416b
green open gl-failures_52 ju4Dh6apRJiFny-xfwX1Uw 2 0 0 0 416b 416b
green open gl-failures_50 A7mJlKcZSdCc7hZ7YJ0WEA 2 0 0 0 416b 416b
green open gl-failures_59 C6U_6QttRU6iHoYiDun5jw 2 0 0 0 416b 416b
green open gl-failures_57 eauYJr__RvKRHMeR18ok7Q 2 0 0 0 416b 416b
green open gl-failures_58 rB193zrQRACereNRZaV6JQ 2 0 0 0 416b 416b
green open gl-system-events_2 Gcj8pHI9SFOJ6gg5HBhZOg 4 0 0 0 832b 832b
green open gl-system-events_0 0VJyfJH-TiuB6HRVtekKIQ 4 0 0 0 832b 832b
green open gl-system-events_1 4SnH4ipSQqKUEhrbzkm4Sg 4 0 0 0 832b 832b
green open gl-failures_66 MBGd-MV2T7WCzmWy_J6MGA 2 0 0 0 416b 416b
green open gl-events_1 6_fhAYxfRw6Q7bgXGEnQww 4 0 7142329 0 1.1gb 1.1gb
green open gl-events_0 5I8vbJacT22BLtDtTyhlNA 4 0 869062 0 150.7mb 150.7mb
green open gl-failures_67 ryEXm_zfTMKg5XgQTmbt6A 2 0 0 0 416b 416b
green open gl-failures_64 NLPR-X2BSOOcjzVD4japjw 2 0 0 0 416b 416b