[[managing-users]] == Managing Users in an esusers Realm The `esusers` command line tool is located in `ES_HOME/bin/shield` and enables several administrative tasks for managing users: * <> * <> * <> * <> * <> [float] [[esusers-add]] === Adding Users The `esusers useradd` command adds a user to your cluster. NOTE: To ensure that Elasticsearch can read the user and role information at startup, run `esusers useradd` as the same user you use to run Elasticsearch. Running the command as root or some other user will update the permissions for the `users` and `users_roles` files and prevent Elasticsearch from accessing them. [source,shell] ---------------------------------------- esusers useradd ---------------------------------------- A username must be at least 1 character and no longer than 30 characters. The first character must be a letter (`a-z` or `A-Z`) or an underscore (`_`). Subsequent characters can be letters, underscores (`_`), digits (`0-9`), or any of the following symbols `@`, `-`, `.` or `$` You can specify the user's password at the command line with the `-p` option. When this option is absent, the `esusers` command prompts you for the password. Omit the `-p` option to keep plaintext passwords out of the terminal session's command history. [source,shell] ---------------------------------------------------- esusers useradd -p ---------------------------------------------------- Passwords must be at least 6 characters long. You can define a user's roles with the `-r` parameter. This parameter accepts a comma-separated list of role names to associate with the user. [source,shell] ------------------------------------------------------------------- esusers useradd -r ------------------------------------------------------------------- The following example adds a new user named `jacknich` to the _esusers_ realm. The password for this user is `theshining`, and this user is associated with the `logstash` and `marvel` roles. [source,shell] --------------------------------------------------------- esusers useradd jacknich -p theshining -r logstash,marvel --------------------------------------------------------- For valid role names please see <>. [float] [[esusers-list]] === Listing Users The `esusers list` command lists the users registered in the _esusers_ realm, as in the following example: [source, shell] ---------------------------------- esusers list rdeniro : admin alpacino : power_user jacknich : marvel,logstash ---------------------------------- Users are in the left-hand column and their corresponding roles are listed in the right-hand column. The `esusers list ` command lists a specific user. Use this command to verify that a user has been successfully added to the cluster. [source,shell] ----------------------------------- esusers list jacknich jacknich : marvel,logstash ----------------------------------- [float] [[esusers-pass]] === Managing User Passwords The `esusers passwd` command enables you to reset a user's password. You can specify the new password directly with the `-p` option. When `-p` option is omitted, the tool will prompt you to enter and confirm a password in interactive mode. [source,shell] -------------------------------------------------- esusers passwd -------------------------------------------------- [source,shell] -------------------------------------------------- esusers passwd -p -------------------------------------------------- [float] [[esusers-roles]] === Assigning Users to Roles The `esusers roles` command manages the roles associated to a particular user. The `-a` option adds a comma-separated list of roles to a user. The `-r` option removes a comma-separated list of roles from a user. You can combine adding and removing roles within the same command to change a user's roles. [source,shell] ------------------------------------------------------------------------------------------------------------ esusers roles -a -r ------------------------------------------------------------------------------------------------------------ The following command removes the `logstash` and `marvel` roles from user `jacknich`, as well as adding the `user` role: [source,shell] --------------------------------------------------------------- esusers roles jacknich -r logstash,marvel -a user --------------------------------------------------------------- Listing the user displays the new role assignment: [source,shell] --------------------------------- esusers list jacknich jacknich : user --------------------------------- [float] [[esusers-del]] === Deleting Users The `esusers userdel` command deletes a user. [source,shell] -------------------------------------------------- userdel -------------------------------------------------- [float] === About `esusers` The `esusers` tool manipulates two files, `users` and `users_roles`, in `CONFIG_DIR/shield/`. These two files store all user data for the _esusers_ realm and are read by Shield on startup. By default, Shield checks these files for changes every 5 seconds. You can change this default behavior by changing the value of the `watcher.interval.high` setting in the `elasticsearch.yml` file. [IMPORTANT] ============================== These files are managed locally by the node and are **not** managed globally by the cluster. This means that with a typical multi-node cluster, the exact same changes need to be applied on each and every node in the cluster. A safer approach would be to apply the change on one of the nodes and have the `users` and `users_roles` files distributed/copied to all other nodes in the cluster (either manually or using a configuration management system such as Puppet or Chef). ============================== While it is possible to modify these files directly using any standard text editor, we strongly recommend using the `esusers` command-line tool to apply the required changes. [float] [[users-file]] ==== The `users` File The `users` file stores all the users and their passwords. Each line in the `users` file represents a single user entry consisting of the username and **hashed** password. [source,bash] ---------------------------------------------------------------------- rdeniro:$2a$10$BBJ/ILiyJ1eBTYoRKxkqbuDEdYECplvxnqQ47uiowE7yGqvCEgj9W alpacino:$2a$10$cNwHnElYiMYZ/T3K4PvzGeJ1KbpXZp2PfoQD.gfaVdImnHOwIuBKS jacknich:$2a$10$GYUNWyABV/Ols/.bcwxuBuuaQzV6WIauW6RdboojxcixBq3LtI3ni ---------------------------------------------------------------------- NOTE: The `esusers` command-line tool uses `bcrypt` to hash the password by default. [float] [[users_defining-roles]] ==== The `users_roles` File The `users_roles` file stores the roles associated with the users, as in the following example: [source,shell] -------------------------------------------------- admin:rdeniro power_user:alpacino,jacknich user:jacknich -------------------------------------------------- Each row maps a role to a comma-separated list of all the users that are associated with that role. [float] [[user-cache]] ==== User Cache The user credentials are not stored on disk in clear text. The esusers creates a `bcrypt` hashes of the passwords and stores those. `bcrypt` is considered to be highly secured hash and by default it uses 10 rounds to generate the salts it hashes with. While highly secured, it is also relatively slow. For this reason, Shield also introduce an in-memory cache over the `esusers` store. This cache can use a different hashing algorithm for storing the passwords in memeory. The default hashing algorithm that is used is `ssha256` - a salted SHA-256 algorithm. We've seen in the table <> that the cache characteristics can be configured. The following table describes the different hash algorithm that can be set: [[esusers-cache-hash-algo]] .Cache hash algorithms |======================= | Algorithm | Description | `ssha256` | Uses a salted `SHA-256` algorithm (default). | `md5` | Uses `MD5` algorithm. | `sha1` | Uses `SHA1` algorithm. | `bcrypt` | Uses `bcrypt` algorithm with salt generated in 10 rounds. | `bcrypt4` | Uses `bcrypt` algorithm with salt generated in 4 rounds. | `bcrypt5` | Uses `bcrypt` algorithm with salt generated in 5 rounds. | `bcrypt6` | Uses `bcrypt` algorithm with salt generated in 6 rounds. | `bcrypt7` | Uses `bcrypt` algorithm with salt generated in 7 rounds. | `bcrypt8` | Uses `bcrypt` algorithm with salt generated in 8 rounds. | `bcrypt9` | Uses `bcrypt` algorithm with salt generated in 9 rounds. | `noop`,`clear_text` | Doesn't hash the credentials and keeps it in clear text in memory. CAUTION: keeping clear text is considered insecure and can be compromised at the OS level (e.g. memory dumps and `ptrace`). |======================= [float] [[cache-eviction-api]] ==== Cache Eviction API Shield exposes an API to force cached user eviction. The following example, evicts all users from the `esusers` realm: [source, java] ------------------------------------------------------------ $ curl -XPOST 'http://localhost:9200/_shield/realm/esusers/_cache/clear' ------------------------------------------------------------ NOTE: if no realm is defined, the default realm name, `default_esusers` can be used to clear the cache of the default esusers realm. It is also possible to evict specific users: [source, java] ------------------------------------------------------------ $ curl -XPOST 'http://localhost:9200/_shield/realm/esusers/_cache/clear?usernames=rdeniro,alpacino' ------------------------------------------------------------ Multiple realms can also be specified using comma-delimited list: [source, java] ------------------------------------------------------------ $ curl -XPOST 'http://localhost:9200/_shield/realm/esusers,ldap1/_cache/clear' ------------------------------------------------------------