HDFS-9570. Minor typos, grammar, and case sensitivity cleanup in HdfsPermissionsGuide.md's (Travis Campbell via aw)
Project: http://git-wip-us.apache.org/repos/asf/hadoop/repo Commit: http://git-wip-us.apache.org/repos/asf/hadoop/commit/8d278d8d Tree: http://git-wip-us.apache.org/repos/asf/hadoop/tree/8d278d8d Diff: http://git-wip-us.apache.org/repos/asf/hadoop/diff/8d278d8d Branch: refs/heads/yarn-2877 Commit: 8d278d8d2e5a8a53308608a8fbc6ba96228e53ef Parents: eb6939c Author: Allen Wittenauer <[email protected]> Authored: Thu Dec 17 08:31:25 2015 -0800 Committer: Allen Wittenauer <[email protected]> Committed: Thu Dec 17 08:31:44 2015 -0800 ---------------------------------------------------------------------- hadoop-hdfs-project/hadoop-hdfs/CHANGES.txt | 3 +++ .../src/site/markdown/HdfsPermissionsGuide.md | 14 +++++++------- 2 files changed, 10 insertions(+), 7 deletions(-) ---------------------------------------------------------------------- http://git-wip-us.apache.org/repos/asf/hadoop/blob/8d278d8d/hadoop-hdfs-project/hadoop-hdfs/CHANGES.txt ---------------------------------------------------------------------- diff --git a/hadoop-hdfs-project/hadoop-hdfs/CHANGES.txt b/hadoop-hdfs-project/hadoop-hdfs/CHANGES.txt index c8e5748..78d67f6 100644 --- a/hadoop-hdfs-project/hadoop-hdfs/CHANGES.txt +++ b/hadoop-hdfs-project/hadoop-hdfs/CHANGES.txt @@ -211,6 +211,9 @@ Trunk (Unreleased) OPTIMIZATIONS BUG FIXES + + HDFS-9570. Minor typos, grammar, and case sensitivity cleanup in + HdfsPermissionsGuide.md's (Travis Campbell via aw) HADOOP-9635 Fix potential Stack Overflow in DomainSocket.c (V. Karthik Kumar via cmccabe) http://git-wip-us.apache.org/repos/asf/hadoop/blob/8d278d8d/hadoop-hdfs-project/hadoop-hdfs/src/site/markdown/HdfsPermissionsGuide.md ---------------------------------------------------------------------- diff --git a/hadoop-hdfs-project/hadoop-hdfs/src/site/markdown/HdfsPermissionsGuide.md b/hadoop-hdfs-project/hadoop-hdfs/src/site/markdown/HdfsPermissionsGuide.md index 450255e..fdeb948 100644 --- a/hadoop-hdfs-project/hadoop-hdfs/src/site/markdown/HdfsPermissionsGuide.md +++ b/hadoop-hdfs-project/hadoop-hdfs/src/site/markdown/HdfsPermissionsGuide.md @@ -34,7 +34,7 @@ Overview The Hadoop Distributed File System (HDFS) implements a permissions model for files and directories that shares much of the POSIX model. Each file and directory is associated with an owner and a group. The file or directory has separate permissions for the user that is the owner, for other users that are members of the group, and for all other users. For files, the r permission is required to read the file, and the w permission is required to write or append to the file. For directories, the r permission is required to list the contents of the directory, the w permission is required to create or delete files or directories, and the x permission is required to access a child of the directory. -In contrast to the POSIX model, there are no setuid or setgid bits for files as there is no notion of executable files. For directories, there are no setuid or setgid bits directory as a simplification. The Sticky bit can be set on directories, preventing anyone except the superuser, directory owner or file owner from deleting or moving the files within the directory. Setting the sticky bit for a file has no effect. Collectively, the permissions of a file or directory are its mode. In general, Unix customs for representing and displaying modes will be used, including the use of octal numbers in this description. When a file or directory is created, its owner is the user identity of the client process, and its group is the group of the parent directory (the BSD rule). +In contrast to the POSIX model, there are no setuid or setgid bits for files as there is no notion of executable files. For directories, there are no setuid or setgid bits directory as a simplification. The sticky bit can be set on directories, preventing anyone except the superuser, directory owner or file owner from deleting or moving the files within the directory. Setting the sticky bit for a file has no effect. Collectively, the permissions of a file or directory are its mode. In general, Unix customs for representing and displaying modes will be used, including the use of octal numbers in this description. When a file or directory is created, its owner is the user identity of the client process, and its group is the group of the parent directory (the BSD rule). HDFS also provides optional support for POSIX ACLs (Access Control Lists) to augment file permissions with finer-grained rules for specific named users or named groups. ACLs are discussed in greater detail later in this document. @@ -61,7 +61,7 @@ As of Hadoop 0.22, Hadoop supports two different modes of operation to determine In Kerberized operation, the identity of a client process is determined by its Kerberos credentials. For example, in a - Kerberized environment, a user may use the kinit utility to + Kerberized environment, a user may use the `kinit` utility to obtain a Kerberos ticket-granting-ticket (TGT) and use klist to determine their current principal. When mapping a Kerberos principal to an HDFS username, all components except for the @@ -84,7 +84,7 @@ Note that HDFS stores the user and group of a file or directory as strings; ther Understanding the Implementation -------------------------------- -Each file or directory operation passes the full path name to the name node, and the permissions checks are applied along the path for each operation. The client framework will implicitly associate the user identity with the connection to the name node, reducing the need for changes to the existing client API. It has always been the case that when one operation on a file succeeds, the operation might fail when repeated because the file, or some directory on the path, no longer exists. For instance, when the client first begins reading a file, it makes a first request to the name node to discover the location of the first blocks of the file. A second request made to find additional blocks may fail. On the other hand, deleting a file does not revoke access by a client that already knows the blocks of the file. With the addition of permissions, a client's access to a file may be withdrawn between requests. Again, changing permissions does not revoke the access of a client that already knows the file's blocks. +Each file or directory operation passes the full path name to the NameNode, and the permissions checks are applied along the path for each operation. The client framework will implicitly associate the user identity with the connection to the NameNode, reducing the need for changes to the existing client API. It has always been the case that when one operation on a file succeeds, the operation might fail when repeated because the file, or some directory on the path, no longer exists. For instance, when the client first begins reading a file, it makes a first request to the NameNode to discover the location of the first blocks of the file. A second request made to find additional blocks may fail. On the other hand, deleting a file does not revoke access by a client that already knows the blocks of the file. With the addition of permissions, a client's access to a file may be withdrawn between requests. Again, changing permissions does not revoke the access of a client that already kno ws the file's blocks. Changes to the File System API ------------------------------ @@ -100,7 +100,7 @@ New methods: * `public void setOwner(Path p, String username, String groupname) throws IOException;` * `public FileStatus getFileStatus(Path f) throws IOException;`will additionally return the user, group and mode associated with the path. -The mode of a new file or directory is restricted my the umask set as a configuration parameter. When the existing `create(path, â¦)` method (without the permission parameter) is used, the mode of the new file is `0666 & ^umask`. When the new `create(path, permission, â¦)` method (with the permission parameter P) is used, the mode of the new file is `P & ^umask & 0666`. When a new directory is created with the existing `mkdirs(path)` method (without the permission parameter), the mode of the new directory is `0777 & ^umask`. When the new `mkdirs(path, permission)` method (with the permission parameter P) is used, the mode of new directory is `P & ^umask & 0777`. +The mode of a new file or directory is restricted by the umask set as a configuration parameter. When the existing `create(path, â¦)` method (without the permission parameter) is used, the mode of the new file is `0666 & ^umask`. When the new `create(path, permission, â¦)` method (with the permission parameter P) is used, the mode of the new file is `P & ^umask & 0666`. When a new directory is created with the existing `mkdirs(path)` method (without the permission parameter), the mode of the new directory is `0777 & ^umask`. When the new `mkdirs(path, permission)` method (with the permission parameter P) is used, the mode of new directory is `P & ^umask & 0777`. Changes to the Application Shell -------------------------------- @@ -129,14 +129,14 @@ New operations: The Super-User -------------- -The super-user is the user with the same identity as name node process itself. Loosely, if you started the name node, then you are the super-user. The super-user can do anything in that permissions checks never fail for the super-user. There is no persistent notion of who was the super-user; when the name node is started the process identity determines who is the super-user for now. The HDFS super-user does not have to be the super-user of the name node host, nor is it necessary that all clusters have the same super-user. Also, an experimenter running HDFS on a personal workstation, conveniently becomes that installation's super-user without any configuration. +The super-user is the user with the same identity as the NameNode process itself. Loosely, if you started the NameNode, then you are the super-user. The super-user can do anything in that permissions checks never fail for the super-user. There is no persistent notion of who was the super-user; when the NameNode is started the process identity determines who is the super-user for now. The HDFS super-user does not have to be the super-user of the NameNode host, nor is it necessary that all clusters have the same super-user. Also, an experimenter running HDFS on a personal workstation, conveniently becomes that installation's super-user without any configuration. -In addition, the administrator my identify a distinguished group using a configuration parameter. If set, members of this group are also super-users. +In addition, the administrator may identify a distinguished group using a configuration parameter. If set, members of this group are also super-users. The Web Server -------------- -By default, the identity of the web server is a configuration parameter. That is, the name node has no notion of the identity of the real user, but the web server behaves as if it has the identity (user and groups) of a user chosen by the administrator. Unless the chosen identity matches the super-user, parts of the name space may be inaccessible to the web server. +By default, the identity of the web server is a configuration parameter. That is, the NameNode has no notion of the identity of the real user, but the web server behaves as if it has the identity (user and groups) of a user chosen by the administrator. Unless the chosen identity matches the super-user, parts of the name space may be inaccessible to the web server. ACLs (Access Control Lists) ---------------------------
