In this examples I am using a Cloudera virtual box but it the same command on HDP.
I didn't create a local user mudassar but used hdfs and the hdfs directory ################################# # Whoami ################################# # id
uid=0(root) gid=0(root) groups=0(root) ################################# # Switched to hdfs user ################################# # su - hdfs ################################# # Changed directory to tmp to create test files ################################# $ cd /tmp ################################# # Created first file ################################# $ echo "This is the first text file for mudassar to test snapshot" > text1.txt ################################# # Created second file ################################# $ echo "Apache Kafka comes with a pluggable authorizer known as Kafka Authorization Command Line (ACL) Interface, which is used for defining users and allowing or denying them to access its various APIs. The default behavior is that only a superuser is allowed to access all the resources of the Kafka cluster, and no other user can access those resources if no proper ACL is defined for those users. The general format in which Kafka ACL is defined is as follows" > text2.txt ################# # Here is output ################ $ ls -lrt
-rw-rw-r-- 1 hdfs hdfs 58 Mar 8 00:34 text1.txt
-rw-rw-r-- 1 cloudera hdfs 456 Mar 8 00:37 text2.txt ################################# # Above I changed the owner of text2.txt to cloudera as root user in the local filesystem ################################# #chown cloudera:hdfs /tmp/text2.txt ################################ # First create a target directory in hdfs ################################ hdfs dfs -mkdir /user/mudassar ################################ # create a snapshottable directory ################################# hdfs dfsadmin -allowSnapshot /user/mudassar output: Allowing snaphot on /user/mudassar succeeded ################################# # Check the snapshottable dir in HDFS ################################# hdfs lsSnapshottableDir Output drwxr-xr-x 0 hdfs supergroup 0 2018-03-08 00:54 0 65536 /user/mudassar ################################# # copy a file from local to the HDFS snapshotable directory ################################# hdfs dfs -put /tmp/text1.txt /user/mudassar ################################# # Validate the files was copied ################################# hdfs dfs -ls /user/mudassar Found 1 items
-rw-r--r-- 1 hdfs supergroup 58 2018-03-08 00:55 /user/mudassar/text1.txt
################################# # create snapshot ################################# hdfs dfs -createSnapshot /user/mudassar Output
Created snapshot /user/mudassar/.snapshot/s20180308-005619.181 ################################# # Check to see the snapshot ################################# hdfs dfs -ls /user/mudassar/.snapshot Output
Found 1 items
drwxr-xr-x - hdfs supergroup 0 2018-03-08 00:56 /user/mudassar/.snapshot/s20180308-005619.181
################################# # copy another file to the directory ################################# hdfs dfs -put /tmp/text2.txt /user/mudassar ################################# # Check the files exit in /user/mudassar notice the timestamp,permissions etc ################################# hdfs dfs -ls /user/mudassar output Found 2 items -rw-r--r-- 1 hdfs supergroup 58 2018-03-08 00:55 /user/mudassar/text1.txt -rw-r--r-- 1 hdfs supergroup 456 2018-03-08 00:58 /user/mudassar/text2.txt ################################# # Changed ownership of one of the files ################################# hdfs dfs -chown cloudera:supergroup /user/mudassar/text2.txt ################################# #Create second snapshot ################################# hdfs dfs -createSnapshot /user/mudassar ################################# # checked the directory notice now we have 2 snapshots one contains ONLY texte1.txt and the other contains both files
################################# $ hdfs dfs -ls /user/mudassar/.snapshot Output Found 2 items drwxr-xr-x - hdfs supergroup 0 2018-03-08 00:56 /user/mudassar/.snapshot/s20180308-005619.181 drwxr-xr-x - hdfs supergroup 0 2018-03-08 01:01 /user/mudassar/.snapshot/s20180308-010152.924
################################# # Simulate accidental deletion of the files ################################# hdfs dfs -rm /user/mudassar/* output 18/03/08 01:06:26 INFO fs.TrashPolicyDefault: Moved: 'hdfs://quickstart.cloudera:8020/user/mudassar/text1.txt' to trash at: hdfs://quickstart.cloudera:8020/user/hdfs/.Trash/Current/user/mudassar/text1.txt 18/03/08 01:06:26 INFO fs.TrashPolicyDefault: Moved: 'hdfs://quickstart.cloudera:8020/user/mudassar/text2.txt' to trash at: hdfs://quickstart.cloudera:8020/user/hdfs/.Trash/Current/user/mudassar/text2.txt ################################# # Validate the files were deleted ################################# hdfs dfs -ls /user/mudassar
Will return nothing but the directory exist, run hdfs dfs -ls /user/ ################################# # check the contents of the latest snapshot xxxxx.924 see above ################################# hdfs dfs -ls -R /user/mudassar/.snapshot/s20180308-010152.924 output -rw-r--r-- 1 hdfs supergroup 58 2018-03-08 00:55 /user/mudassar/.snapshot/s20180308-010152.924/text1.txt -rw-r--r-- 1 cloudera supergroup 456 2018-03-08 00:58 /user/mudassar/.snapshot/s20180308-010152.924/text2.txt ################################# # Recover the 2 files from snapshot using -ptopax option ################################# hdfs dfs -cp -ptopax /user/mudassar/.snapshot/s20180308-010152.924/* /user/mudassar/ ################################# # Validate the files were restored with original timestamps, ownership, permission, ACLs and XAttrs.
################################# hdfs dfs -ls /user/mudassar output -rw-r--r-- 1 hdfs supergroup 58 2018-03-08 00:55 /user/mudassar/text1.txt -rw-r--r-- 1 cloudera supergroup 456 2018-03-08 00:58 /user/mudassar/text2.txt There you are recovered the 2 files delete accidentally ,please let me know if that worked out for you
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