Docs: Merge EE doc/​administration/​auth to CE

11 files changed, 871 insertions, 6 deletions

diff --git a/doc/administration/auth/README.md b/doc/administration/auth/README.md
index 54be7b616cc..e215a0df6ec 100644
--- a/doc/administration/auth/README.md
+++ b/doc/administration/auth/README.md
@@ -9,9 +9,11 @@ providers.
 
 - [LDAP](ldap.md) Includes Active Directory, Apple Open Directory, Open LDAP,
   and 389 Server
+  - [LDAP for GitLab EE](ldap-ee.md): LDAP additions to GitLab Enterprise Editions **[STARTER ONLY]**
 - [OmniAuth](../../integration/omniauth.md) Sign in via Twitter, GitHub, GitLab.com, Google,
   Bitbucket, Facebook, Shibboleth, Crowd, Azure, Authentiq ID, and JWT
 - [CAS](../../integration/cas.md) Configure GitLab to sign in using CAS
 - [SAML](../../integration/saml.md) Configure GitLab as a SAML 2.0 Service Provider
 - [Okta](okta.md) Configure GitLab to sign in using Okta
 - [Authentiq](authentiq.md): Enable the Authentiq OmniAuth provider for passwordless authentication
+- [Smartcard](smartcard.md) Smartcard authentication **[PREMIUM ONLY]**
diff --git a/doc/administration/auth/how_to_configure_ldap_gitlab_ce/index.md b/doc/administration/auth/how_to_configure_ldap_gitlab_ce/index.md
index 8d81b32e721..1f67e8f5744 100644
--- a/doc/administration/auth/how_to_configure_ldap_gitlab_ce/index.md
+++ b/doc/administration/auth/how_to_configure_ldap_gitlab_ce/index.md
@@ -14,7 +14,7 @@ Managing a large number of users in GitLab can become a burden for system admini
 
 In this guide we will focus on configuring GitLab with Active Directory. [Active Directory](https://en.wikipedia.org/wiki/Active_Directory) is a popular LDAP compatible directory service provided by Microsoft, included in all modern Windows Server operating systems.
 
-GitLab has supported LDAP integration since [version 2.2](https://about.gitlab.com/2012/02/22/gitlab-version-2-2/). With GitLab LDAP [group syncing](https://docs.gitlab.com/ee/administration/auth/how_to_configure_ldap_gitlab_ee/index.html#group-sync) being added to GitLab Enterprise Edition in [version 6.0](https://about.gitlab.com/2013/08/20/gitlab-6-dot-0-released/). LDAP integration has become one of the most popular features in GitLab.
+GitLab has supported LDAP integration since [version 2.2](https://about.gitlab.com/2012/02/22/gitlab-version-2-2/). With GitLab LDAP [group syncing](../how_to_configure_ldap_gitlab_ee/index.html#group-sync) being added to GitLab Enterprise Edition in [version 6.0](https://about.gitlab.com/2013/08/20/gitlab-6-dot-0-released/). LDAP integration has become one of the most popular features in GitLab.
 
 ## Getting started
 
@@ -111,7 +111,7 @@ The initial configuration of LDAP in GitLab requires changes to the `gitlab.rb`
 
 The two Active Directory specific values are `active_directory: true` and `uid: 'sAMAccountName'`. `sAMAccountName` is an attribute returned by Active Directory used for GitLab usernames. See the example output from `ldapsearch` for a full list of attributes a "person" object (user) has in **AD** - [`ldapsearch` example](#using-ldapsearch-unix)
 
-> Both group_base and admin_group configuration options are only available in GitLab Enterprise Edition. See [GitLab EE - LDAP Features](https://docs.gitlab.com/ee/administration/auth/how_to_configure_ldap_gitlab_ee/index.html#gitlab-enterprise-edition---ldap-features)
+> Both group_base and admin_group configuration options are only available in GitLab Enterprise Edition. See [GitLab EE - LDAP Features](../how_to_configure_ldap_gitlab_ee/index.html#gitlab-enterprise-edition---ldap-features) **[STARTER ONLY]**
 
 ### Example `gitlab.rb` LDAP
 
@@ -267,4 +267,4 @@ have extended functionalities with LDAP, such as:
 - Updating user permissions
 - Multiple LDAP servers
 
-Read through the article on [LDAP for GitLab EE](https://docs.gitlab.com/ee/administration/auth/how_to_configure_ldap_gitlab_ee/) for an overview.
+Read through the article on [LDAP for GitLab EE](../how_to_configure_ldap_gitlab_ee/index.md) **[STARTER ONLY]** for an overview.
diff --git a/doc/administration/auth/how_to_configure_ldap_gitlab_ee/img/admin_group.png b/doc/administration/auth/how_to_configure_ldap_gitlab_ee/img/admin_group.png
new file mode 100644
index 00000000000..9896379d669
--- /dev/null
+++ b/doc/administration/auth/how_to_configure_ldap_gitlab_ee/img/admin_group.png
diff --git a/doc/administration/auth/how_to_configure_ldap_gitlab_ee/img/group_link_final.png b/doc/administration/auth/how_to_configure_ldap_gitlab_ee/img/group_link_final.png
new file mode 100644
index 00000000000..21fb5a7d0ce
--- /dev/null
+++ b/doc/administration/auth/how_to_configure_ldap_gitlab_ee/img/group_link_final.png
diff --git a/doc/administration/auth/how_to_configure_ldap_gitlab_ee/img/group_linking.gif b/doc/administration/auth/how_to_configure_ldap_gitlab_ee/img/group_linking.gif
new file mode 100644
index 00000000000..d35cf55804f
--- /dev/null
+++ b/doc/administration/auth/how_to_configure_ldap_gitlab_ee/img/group_linking.gif
diff --git a/doc/administration/auth/how_to_configure_ldap_gitlab_ee/img/manual_permissions.gif b/doc/administration/auth/how_to_configure_ldap_gitlab_ee/img/manual_permissions.gif
new file mode 100644
index 00000000000..29b28df1cbd
--- /dev/null
+++ b/doc/administration/auth/how_to_configure_ldap_gitlab_ee/img/manual_permissions.gif
diff --git a/doc/administration/auth/how_to_configure_ldap_gitlab_ee/img/multi_login.gif b/doc/administration/auth/how_to_configure_ldap_gitlab_ee/img/multi_login.gif
new file mode 100644
index 00000000000..d317add9837
--- /dev/null
+++ b/doc/administration/auth/how_to_configure_ldap_gitlab_ee/img/multi_login.gif
diff --git a/doc/administration/auth/how_to_configure_ldap_gitlab_ee/index.md b/doc/administration/auth/how_to_configure_ldap_gitlab_ee/index.md
new file mode 100644
index 00000000000..4d82a7370bb
--- /dev/null
+++ b/doc/administration/auth/how_to_configure_ldap_gitlab_ee/index.md
@@ -0,0 +1,119 @@
+---
+author: Chris Wilson
+author_gitlab: MrChrisW
+level: intermediary
+article_type: admin guide
+date: 2017-05-03
+---
+
+# How to configure LDAP with GitLab EE **[STARTER ONLY]**
+
+## Introduction
+
+The present article follows [How to Configure LDAP with GitLab CE](../how_to_configure_ldap_gitlab_ce/index.md). Make sure to read through it before moving forward.
+
+## GitLab Enterprise Edition - LDAP features
+
+[GitLab Enterprise Edition (EE)](https://about.gitlab.com/pricing/) has a number of advantages when it comes to integrating with Active Directory (LDAP):
+
+- [Administrator Sync](../ldap-ee.md#administrator-sync): As an extension of group sync, you can automatically manage your global GitLab administrators. Specify a group CN for `admin_group` and all members of the LDAP group will be given administrator privileges.
+- [Group Sync](#group-sync): This allows GitLab group membership to be automatically updated based on LDAP group members.
+- [Multiple LDAP servers](#multiple-ldap-servers): The ability to configure multiple LDAP servers. This is useful if an organization has different LDAP servers within departments. This is not designed for failover. We're working on [supporting LDAP failover](https://gitlab.com/gitlab-org/gitlab-ee/issues/139) in GitLab.
+
+- Daily user synchronization: Once a day, GitLab will run a synchronization to check and update GitLab users against LDAP. This process updates all user details automatically.
+
+On the following section, you'll find a description for each of these features. Read through [LDAP GitLab EE docs](../ldap-ee.md) for complementary information.
+
+![GitLab OU Structure](img/admin_group.png)
+
+All members of the group `Global Admins` will be given **administrator** access to GitLab, allowing them to view the `/admin` dashboard.
+
+### Group Sync
+
+Group syncing allows AD (LDAP) groups to be mapped to GitLab groups. This provides more control over per-group user management. To configure group syncing edit the `group_base` **DN** (`'OU=Global Groups,OU=GitLab INT,DC=GitLab,DC=org'`). This **OU** contains all groups that will be associated with [GitLab groups](../../../user/group/index.md).
+
+#### Creating group links - example
+
+As an example, let's suppose we have a "UKGov" GitLab group, which deals with confidential government information. Therefore, it is important that users of this group are given the correct permissions to projects contained within the group. Granular group permissions can be applied based on the AD group.
+
+**UK Developers** of our "UKGov" group are given **"developer"** permissions.
+
+_The developer permission allows the development staff to effectively manage all project code, issues, and merge requests._
+
+**UK Support** staff of our "UKGov" group are given **"reporter"** permissions.
+
+_The reporter permission allows support staff to manage issues, labels, and review project code._
+
+**US People Ops** of our "UKGov" group are given **"guest"** permissions.
+
+![Creating group links](img/group_linking.gif)
+
+> Guest permissions allows people ops staff to review and lodge new issues while allowing no read or write access to project code or [confidential issues](../../../user/project/issues/confidential_issues.md#permissions-and-access-to-confidential-issues) created by other users.
+
+See the [permission list](../../../user/permissions.md) for complementary info.
+
+#### Group permissions - example
+
+Considering the previous example, our staff will have
+access to our GitLab instance with the following structure:
+
+![GitLab OU Structure](img/group_link_final.png)
+
+Using this permission structure in our example allows only UK staff access to sensitive information stored in the projects code, while still allowing other teams to work effectively. As all permissions are controlled via AD groups new users can be quickly added to existing groups. New group members will then automatically inherit the required permissions.
+
+> [More information](../ldap-ee.md#group-sync) on group syncing.
+
+### Updating user permissions - new feature
+
+Since GitLab [v8.15](https://gitlab.com/gitlab-org/gitlab-ee/merge_requests/822) LDAP user permissions can now be manually overridden by an admin user. To override a user's permissions visit the groups **Members** page and select **Edit permissions**.
+
+![Setting manual permissions](img/manual_permissions.gif)
+
+### Multiple LDAP servers
+
+GitLab EE can support multiple LDAP servers. Simply configure another server in the `gitlab.rb` file within the `ldap_servers` block. In the example below we configure a new secondary server with the label **GitLab Secondary AD**. This is shown on the GitLab login screen. Large enterprises often utilize multiple LDAP servers for segregating organizational departments.
+
+![Multiple LDAP Servers Login](img/multi_login.gif)
+
+Considering the example illustrated on the image above,
+our `gitlab.rb` configuration would look like:
+
+```ruby
+gitlab_rails['ldap_enabled'] = true
+gitlab_rails['ldap_servers'] = {
+'main' => {
+  'label' => 'GitLab AD',
+  'host' =>  'ad.example.org',
+  'port' => 636,
+  'uid' => 'sAMAccountName',
+  'method' => 'ssl',
+  'bind_dn' => 'CN=GitLabSRV,CN=Users,DC=GitLab,DC=org',
+  'password' => 'Password1',
+  'active_directory' => true,
+  'base' => 'OU=GitLab INT,DC=GitLab,DC=org',
+  'group_base' => 'OU=Global Groups,OU=GitLab INT,DC=GitLab,DC=org',
+  'admin_group' => 'Global Admins'
+  },
+
+'secondary' => {
+  'label' => 'GitLab Secondary AD',
+  'host' =>  'ad-secondary.example.net',
+  'port' => 636,
+  'uid' => 'sAMAccountName',
+  'method' => 'ssl',
+  'bind_dn' => 'CN=GitLabSRV,CN=Users,DC=GitLab,DC=com',
+  'password' => 'Password1',
+  'active_directory' => true,
+  'base' => 'OU=GitLab Secondary,DC=GitLab,DC=com',
+  'group_base' => 'OU=Global Groups,OU=GitLab INT,DC=GitLab,DC=com',
+  'admin_group' => 'Global Admins'
+  }
+}
+```
+
+## Conclusion
+
+Integration of GitLab with Active Directory (LDAP) reduces the complexity of user management.
+It has the advantage of improving user permission controls, whilst easing the deployment of GitLab into an existing [IT environment](https://www.techopedia.com/definition/29199/it-infrastructure). GitLab EE offers advanced group management and multiple LDAP servers.
+
+With the assistance of the [GitLab Support](https://about.gitlab.com/support) team, setting up GitLab with an existing AD/LDAP solution will be a smooth and painless process.
diff --git a/doc/administration/auth/ldap-ee.md b/doc/administration/auth/ldap-ee.md
new file mode 100644
index 00000000000..30095d35705
--- /dev/null
+++ b/doc/administration/auth/ldap-ee.md
@@ -0,0 +1,557 @@
+# LDAP Additions in GitLab EE **[STARTER ONLY]**
+
+This is a continuation of the main [LDAP documentation](ldap.md), detailing LDAP
+features specific to GitLab Enterprise Edition Starter, Premium and Ultimate.
+
+## Overview
+
+[LDAP](https://en.wikipedia.org/wiki/Lightweight_Directory_Access_Protocol)
+stands for **Lightweight Directory Access Protocol**, which
+is a standard application protocol for
+accessing and maintaining distributed directory information services
+over an Internet Protocol (IP) network.
+
+GitLab integrates with LDAP to support **user authentication**. This integration
+works with most LDAP-compliant directory servers, including Microsoft Active
+Directory, Apple Open Directory, Open LDAP, and 389 Server.
+**GitLab Enterprise Edition** includes enhanced integration, including group
+membership syncing.
+
+## Use cases
+
+- User sync: Once a day, GitLab will update users against LDAP
+- Group sync: Once an hour, GitLab will update group membership
+  based on LDAP group members
+
+## Multiple LDAP servers
+
+With GitLab Enterprise Edition Starter, you can configure multiple LDAP servers
+that your GitLab instance will connect to.
+
+To add another LDAP server, you can start by duplicating the settings under
+[the main configuration](ldap.md#configuration) and edit them to match the
+additional LDAP server.
+
+Be sure to choose a different provider ID made of letters a-z and numbers 0-9.
+This ID will be stored in the database so that GitLab can remember which LDAP
+server a user belongs to.
+
+## User sync
+
+Once per day, GitLab will run a worker to check and update GitLab
+users against LDAP.
+
+The process will execute the following access checks:
+
+1. Ensure the user is still present in LDAP
+1. If the LDAP server is Active Directory, ensure the user is active (not
+   blocked/disabled state). This will only be checked if
+   `active_directory: true` is set in the LDAP configuration [^1]
+
+The user will be set to `ldap_blocked` state in GitLab if the above conditions
+fail. This means the user will not be able to login or push/pull code.
+
+The process will also update the following user information:
+
+1. Email address
+1. If `sync_ssh_keys` is set, SSH public keys
+1. If Kerberos is enabled, Kerberos identity
+
+NOTE: **Note:**
+The LDAP sync process updates existing users while new users will
+be created on first sign in.
+
+## Group Sync
+
+If your LDAP supports the `memberof` property, when the user signs in for the
+first time GitLab will trigger a sync for groups the user should be a member of.
+That way they don't need to wait for the hourly sync to be granted
+access to their groups and projects.
+
+In GitLab Premium, we can also add a GitLab group to sync with one or multiple LDAP groups or we can
+also add a filter. The filter must comply with the syntax defined in [RFC 2254](https://tools.ietf.org/search/rfc2254).
+
+A group sync process will run every hour on the hour, and `group_base` must be set
+in LDAP configuration for LDAP synchronizations based on group CN to work. This allows
+GitLab group membership to be automatically updated based on LDAP group members.
+
+The `group_base` configuration should be a base LDAP 'container', such as an
+'organization' or 'organizational unit', that contains LDAP groups that should
+be available to GitLab. For example, `group_base` could be
+`ou=groups,dc=example,dc=com`. In the config file it will look like the
+following.
+
+**Omnibus configuration**
+
+1. Edit `/etc/gitlab/gitlab.rb`:
+
+    ```ruby
+    gitlab_rails['ldap_servers'] = YAML.load <<-EOS
+    main:
+      ## snip...
+      ##
+      ## Base where we can search for groups
+      ##
+      ##   Ex. ou=groups,dc=gitlab,dc=example
+      ##
+      ##
+      group_base: ou=groups,dc=example,dc=com
+    EOS
+    ```
+
+1. [Reconfigure GitLab][reconfigure] for the changes to take effect.
+
+**Source configuration**
+
+1. Edit `/home/git/gitlab/config/gitlab.yml`:
+
+    ```yaml
+    production:
+      ldap:
+        servers:
+          main:
+            # snip...
+            group_base: ou=groups,dc=example,dc=com
+    ```
+
+1. [Restart GitLab][restart] for the changes to take effect.
+
+---
+
+To take advantage of group sync, group owners or maintainers will need to create an
+LDAP group link in their group **Settings > LDAP Groups** page. Multiple LDAP
+groups and/or filters can be linked with a single GitLab group. When the link is
+created, an access level/role is specified (Guest, Reporter, Developer, Maintainer,
+or Owner).
+
+## Administrator sync
+
+As an extension of group sync, you can automatically manage your global GitLab
+administrators. Specify a group CN for `admin_group` and all members of the
+LDAP group will be given administrator privileges. The configuration will look
+like the following.
+
+NOTE: **Note:**
+Administrators will not be synced unless `group_base` is also
+specified alongside `admin_group`. Also, only specify the CN of the admin
+group, as opposed to the full DN.
+
+**Omnibus configuration**
+
+1. Edit `/etc/gitlab/gitlab.rb`:
+
+    ```ruby
+    gitlab_rails['ldap_servers'] = YAML.load <<-EOS
+    main:
+      ## snip...
+      ##
+      ## Base where we can search for groups
+      ##
+      ##   Ex. ou=groups,dc=gitlab,dc=example
+      ##
+      ##
+      group_base: ou=groups,dc=example,dc=com
+
+      ##
+      ## The CN of a group containing GitLab administrators
+      ##
+      ##   Ex. administrators
+      ##
+      ##   Note: Not `cn=administrators` or the full DN
+      ##
+      ##
+      admin_group: my_admin_group
+
+    EOS
+    ```
+
+1. [Reconfigure GitLab][reconfigure] for the changes to take effect.
+
+**Source configuration**
+
+1. Edit `/home/git/gitlab/config/gitlab.yml`:
+
+    ```yaml
+    production:
+      ldap:
+        servers:
+          main:
+            # snip...
+            group_base: ou=groups,dc=example,dc=com
+            admin_group: my_admin_group
+    ```
+
+1. [Restart GitLab][restart] for the changes to take effect.
+
+## Adjusting LDAP user sync schedule
+
+> Introduced in GitLab Enterprise Edition Starter.
+
+NOTE: **Note:**
+These are cron formatted values. You can use a crontab generator to create
+these values, for example http://www.crontabgenerator.com/.
+
+By default, GitLab will run a worker once per day at 01:30 a.m. server time to
+check and update GitLab users against LDAP.
+
+You can manually configure LDAP user sync times by setting the
+following configuration values. The example below shows how to set LDAP user
+sync to run once every 12 hours at the top of the hour. 
+
+**Omnibus installations**
+
+1. Edit `/etc/gitlab/gitlab.rb`:
+
+    ```ruby
+    gitlab_rails['ldap_sync_worker_cron'] = "0 */12 * * *"
+    ```
+
+1. [Reconfigure GitLab](../restart_gitlab.md#omnibus-gitlab-reconfigure) for the changes to take effect.
+
+**Source installations**
+
+1. Edit `config/gitlab.yaml`:
+
+    ```yaml
+    cron_jobs:
+      ldap_sync_worker_cron:
+        "0 */12 * * *"
+    ```
+
+1. [Restart GitLab](../restart_gitlab.md#installations-from-source) for the changes to take effect.
+
+## Adjusting LDAP group sync schedule
+
+NOTE: **Note:**
+These are cron formatted values. You can use a crontab generator to create
+these values, for example http://www.crontabgenerator.com/.
+
+By default, GitLab will run a group sync process every hour, on the hour.
+
+CAUTION: **Important:**
+It's recommended that you do not run too short intervals as this
+could lead to multiple syncs running concurrently. This is primarily a concern
+for installations with a large number of LDAP users. Please review the
+[LDAP group sync benchmark metrics](#benchmarks) to see how
+your installation compares before proceeding.
+
+You can manually configure LDAP group sync times by setting the
+following configuration values. The example below shows how to set group 
+sync to run once every 2 hours at the top of the hour. 
+
+**Omnibus installations**
+
+1. Edit `/etc/gitlab/gitlab.rb`:
+
+    ```ruby
+    gitlab_rails['ldap_group_sync_worker_cron'] = "0 */2 * * * *"
+    ```
+
+1. [Reconfigure GitLab](../restart_gitlab.md#omnibus-gitlab-reconfigure) for the changes to take effect.
+
+**Source installations**
+
+1. Edit `config/gitlab.yaml`:
+
+    ```yaml
+    cron_jobs:
+      ldap_group_sync_worker_cron:
+          "*/30 * * * *"
+    ```
+
+1. [Restart GitLab](../restart_gitlab.md#installations-from-source) for the changes to take effect.
+
+## External groups
+
+> Introduced in GitLab Enterprise Edition Starter 8.9.
+
+Using the `external_groups` setting will allow you to mark all users belonging
+to these groups as [external users](../../user/permissions.md#external-users-permissions).
+Group membership is checked periodically through the `LdapGroupSync` background
+task.
+
+**Omnibus configuration**
+
+1. Edit `/etc/gitlab/gitlab.rb`:
+
+    ```ruby
+    gitlab_rails['ldap_servers'] = YAML.load <<-EOS
+    main:
+      ## snip...
+      ##
+      ## An array of CNs of groups containing users that should be considered external
+      ##
+      ##   Ex. ['interns', 'contractors']
+      ##
+      ##   Note: Not `cn=interns` or the full DN
+      ##
+      external_groups: ['interns', 'contractors']
+    EOS
+    ```
+
+1. [Reconfigure GitLab][reconfigure] for the changes to take effect.
+
+**Source configuration**
+
+1. Edit `config/gitlab.yaml`:
+
+    ```yaml
+    production:
+      ldap:
+        servers:
+          main:
+            # snip...
+            external_groups: ['interns', 'contractors']
+    ```
+
+1. [Restart GitLab][restart] for the changes to take effect.
+
+## Group sync technical details
+
+There is a lot going on with group sync 'under the hood'. This section
+outlines what LDAP queries are executed and what behavior you can expect
+from group sync.
+
+Group member access will be downgraded from a higher level if their LDAP group
+membership changes. For example, if a user has 'Owner' rights in a group and the
+next group sync reveals they should only have 'Developer' privileges, their
+access will be adjusted accordingly. The only exception is if the user is the
+*last* owner in a group. Groups need at least one owner to fulfill
+administrative duties.
+
+### Supported LDAP group types/attributes
+
+GitLab supports LDAP groups that use member attributes `member`, `submember`,
+`uniquemember`, `memberof` and `memberuid`. This means group sync supports, at
+least, LDAP groups with object class `groupOfNames`, `posixGroup`, and
+`groupOfUniqueName`. Other object classes should work fine as long as members
+are defined as one of the mentioned attributes. This also means GitLab supports
+Microsoft Active Directory, Apple Open Directory, Open LDAP, and 389 Server.
+Other LDAP servers should work, too.
+
+Active Directory also supports nested groups. Group sync will recursively
+resolve membership if `active_directory: true` is set in the configuration file.
+
+> **Note:** Nested group membership will only be resolved if the nested group
+  also falls within the configured `group_base`. For example, if GitLab sees a
+  nested group with DN `cn=nested_group,ou=special_groups,dc=example,dc=com` but
+  the configured `group_base` is `ou=groups,dc=example,dc=com`, `cn=nested_group`
+  will be ignored.
+
+### Queries
+
+- Each LDAP group is queried a maximum of one time with base `group_base` and
+  filter `(cn=<cn_from_group_link>)`.
+- If the LDAP group has the `memberuid` attribute, GitLab will execute another
+  LDAP query per member to obtain each user's full DN. These queries are
+  executed with base `base`, scope 'base object', and a filter depending on
+  whether `user_filter` is set. Filter may be `(uid=<uid_from_group>)` or a
+  joining of `user_filter`.
+
+### Benchmarks
+
+Group sync was written to be as performant as possible. Data is cached, database
+queries are optimized, and LDAP queries are minimized. The last benchmark run
+revealed the following metrics:
+
+For 20,000 LDAP users, 11,000 LDAP groups and 1,000 GitLab groups with 10
+LDAP group links each:
+
+- Initial sync (no existing members assigned in GitLab) took 1.8 hours
+- Subsequent syncs (checking membership, no writes) took 15 minutes
+
+These metrics are meant to provide a baseline and performance may vary based on
+any number of factors. This was a pretty extreme benchmark and most instances will
+not have near this many users or groups. Disk speed, database performance,
+network and LDAP server response time will affect these metrics.
+
+## Troubleshooting
+
+### Referral error
+
+If you see `LDAP search error: Referral` in the logs, or when troubleshooting
+LDAP Group Sync, this error may indicate a configuration problem. The LDAP
+configuration `/etc/gitlab/gitlab.rb` (Omnibus) or `config/gitlab.yml` (source)
+is in YAML format and is sensitive to indentation. Check that `group_base` and
+`admin_group` configuration keys are indented 2 spaces past the server
+identifier. The default identifier is `main` and an example snippet looks like
+the following:
+
+```yaml
+main: # 'main' is the GitLab 'provider ID' of this LDAP server
+  label: 'LDAP'
+  host: 'ldap.example.com'
+  ...
+  group_base: 'cn=my_group,ou=groups,dc=example,dc=com'
+  admin_group: 'my_admin_group'
+```
+
+[reconfigure]: ../restart_gitlab.md#omnibus-gitlab-reconfigure
+[restart]: ../restart_gitlab.md#installations-from-source
+
+[^1]: In Active Directory, a user is marked as disabled/blocked if the user
+      account control attribute (`userAccountControl:1.2.840.113556.1.4.803`)
+      has bit 2 set. See https://ctogonewild.com/2009/09/03/bitmask-searches-in-ldap/
+      for more information.
+
+### User DN has changed
+
+When an LDAP user is created in GitLab, their LDAP DN is stored for later reference.
+
+If GitLab cannot find a user by their DN, it will attempt to fallback
+to finding the user by their email. If the lookup is successful, GitLab will
+update the stored DN to the new value.
+
+### User is not being added to a group
+
+Sometimes you may think a particular user should be added to a GitLab group via
+LDAP group sync, but for some reason it's not happening. There are several
+things to check to debug the situation.
+
+- Ensure LDAP configuration has a `group_base` specified. This configuration is
+  required for group sync to work properly.
+- Ensure the correct LDAP group link is added to the GitLab group. Check group
+  links by visiting the GitLab group, then **Settings dropdown -> LDAP groups**.
+- Check that the user has an LDAP identity
+  1. Sign in to GitLab as an administrator user.
+  1. Navigate to **Admin area -> Users**.
+  1. Search for the user
+  1. Open the user, by clicking on their name. Do not click 'Edit'.
+  1. Navigate to the **Identities** tab. There should be an LDAP identity with
+     an LDAP DN as the 'Identifier'.
+
+If all of the above looks good, jump in to a little more advanced debugging.
+Often, the best way to learn more about why group sync is behaving a certain
+way is to enable debug logging. There is verbose output that details every
+step of the sync.
+
+1. Start a Rails console
+
+    ```bash
+    # For Omnibus installations
+    sudo gitlab-rails console
+
+    # For installations from source
+    sudo -u git -H bundle exec rails console production
+    ```
+1. Set the log level to debug (only for this session):
+
+    ```ruby
+    Rails.logger.level = Logger::DEBUG
+    ```
+1. Choose a GitLab group to test with. This group should have an LDAP group link
+   already configured. If the output is `nil`, the group could not be found.
+   If a bunch of group attributes are output, your group was found successfully.
+
+    ```ruby
+    group = Group.find_by(name: 'my_group')
+
+    # Output
+    => #<Group:0x007fe825196558 id: 1234, name: "my_group"...>
+    ```
+1. Run a group sync for this particular group.
+
+    ```ruby
+    EE::Gitlab::Auth::LDAP::Sync::Group.execute_all_providers(group)
+    ```
+1. Look through the output of the sync. See [example log output](#example-log-output)
+   below for more information about the output.
+1. If you still aren't able to see why the user isn't being added, query the
+   LDAP group directly to see what members are listed. Still in the Rails console,
+   run the following query:
+
+    ```ruby
+    adapter = Gitlab::Auth::LDAP::Adapter.new('ldapmain') # If `main` is the LDAP provider
+    ldap_group = EE::Gitlab::Auth::LDAP::Group.find_by_cn('group_cn_here', adapter)
+
+    # Output
+    => #<EE::Gitlab::Auth::LDAP::Group:0x007fcbdd0bb6d8
+    ```
+1. Query the LDAP group's member DNs and see if the user's DN is in the list.
+   One of the DNs here should match the 'Identifier' from the LDAP identity
+   checked earlier. If it doesn't, the user does not appear to be in the LDAP
+   group.
+
+    ```ruby
+    ldap_group.member_dns
+
+    # Output
+    => ["uid=john,ou=people,dc=example,dc=com", "uid=mary,ou=people,dc=example,dc=com"]
+    ```
+1. Some LDAP servers don't store members by DN. Rather, they use UIDs instead.
+   If you didn't see results from the last query, try querying by UIDs instead.
+
+    ```ruby
+    ldap_group.member_uids
+
+    # Output
+    => ['john','mary']
+    ```
+
+#### Example log output
+
+The output of the last command will be very verbose, but contains lots of
+helpful information. For the most part you can ignore log entries that are SQL
+statements.
+
+Indicates the point where syncing actually begins:
+
+```bash
+Started syncing all providers for 'my_group' group
+```
+
+The follow entry shows an array of all user DNs GitLab sees in the LDAP server.
+Note that these are the users for a single LDAP group, not a GitLab group. If
+you have multiple LDAP groups linked to this GitLab group, you will see multiple
+log entries like this - one for each LDAP group. If you don't see an LDAP user
+DN in this log entry, LDAP is not returning the user when we do the lookup.
+Verify the user is actually in the LDAP group.
+
+```bash
+Members in 'ldap_group_1' LDAP group: ["uid=john0,ou=people,dc=example,dc=com",
+"uid=mary0,ou=people,dc=example,dc=com", "uid=john1,ou=people,dc=example,dc=com",
+"uid=mary1,ou=people,dc=example,dc=com", "uid=john2,ou=people,dc=example,dc=com",
+"uid=mary2,ou=people,dc=example,dc=com", "uid=john3,ou=people,dc=example,dc=com",
+"uid=mary3,ou=people,dc=example,dc=com", "uid=john4,ou=people,dc=example,dc=com",
+"uid=mary4,ou=people,dc=example,dc=com"]
+```
+
+Shortly after each of the above entries, you will see a hash of resolved member
+access levels. This hash represents all user DNs GitLab thinks should have
+access to this group, and at which access level (role). This hash is additive,
+and more DNs may be added, or existing entries modified, based on additional
+LDAP group lookups. The very last occurrence of this entry should indicate
+exactly which users GitLab believes should be added to the group.
+
+> **Note:** 10 is 'Guest', 20 is 'Reporter', 30 is 'Developer', 40 is 'Maintainer'
+  and 50 is 'Owner'
+
+```bash
+Resolved 'my_group' group member access: {"uid=john0,ou=people,dc=example,dc=com"=>30,
+"uid=mary0,ou=people,dc=example,dc=com"=>30, "uid=john1,ou=people,dc=example,dc=com"=>30,
+"uid=mary1,ou=people,dc=example,dc=com"=>30, "uid=john2,ou=people,dc=example,dc=com"=>30,
+"uid=mary2,ou=people,dc=example,dc=com"=>30, "uid=john3,ou=people,dc=example,dc=com"=>30,
+"uid=mary3,ou=people,dc=example,dc=com"=>30, "uid=john4,ou=people,dc=example,dc=com"=>30,
+"uid=mary4,ou=people,dc=example,dc=com"=>30}
+```
+
+It's not uncommon to see warnings like the following. These indicate that GitLab
+would have added the user to a group, but the user could not be found in GitLab.
+Usually this is not a cause for concern.
+
+If you think a particular user should already exist in GitLab, but you're seeing
+this entry, it could be due to a mismatched DN stored in GitLab. See
+[User DN has changed](#User-DN-has-changed) to update the user's LDAP identity.
+
+```bash
+User with DN `uid=john0,ou=people,dc=example,dc=com` should have access
+to 'my_group' group but there is no user in GitLab with that
+identity. Membership will be updated once the user signs in for
+the first time.
+```
+
+Finally, the following entry says syncing has finished for this group:
+
+```bash
+Finished syncing all providers for 'my_group' group
+```
diff --git a/doc/administration/auth/ldap.md b/doc/administration/auth/ldap.md
index 2d057dc7509..423a79c56d8 100644
--- a/doc/administration/auth/ldap.md
+++ b/doc/administration/auth/ldap.md
@@ -14,7 +14,7 @@ including group membership syncing as well as multiple LDAP servers support.
 
 The information on this page is relevant for both GitLab CE and EE. For more
 details about EE-specific LDAP features, see the
-[LDAP Enterprise Edition documentation](https://docs.gitlab.com/ee/administration/auth/ldap-ee.html).
+[LDAP Enterprise Edition documentation](ldap-ee.md). **[STARTER ONLY]**
 
 ## Security
 
@@ -39,7 +39,7 @@ immediately block all access.
 
 NOTE: **Note**:
 GitLab Enterprise Edition Starter supports a
-[configurable sync time](https://docs.gitlab.com/ee/administration/auth/ldap-ee.html#adjusting-ldap-user-and-group-sync-schedules),
+[configurable sync time](ldap-ee.md#adjusting-ldap-user-sync-schedule),
 with a default of one hour.
 
 ## Git password authentication
@@ -64,6 +64,7 @@ to connect to one GitLab server.
 
 For a complete guide on configuring LDAP with GitLab Community Edition, please check
 the admin guide [How to configure LDAP with GitLab CE](how_to_configure_ldap_gitlab_ce/index.md).
+For GitLab Enterprise Editions, see also [How to configure LDAP with GitLab EE](how_to_configure_ldap_gitlab_ee/index.md). **[STARTER ONLY]**
 
 To enable LDAP integration you need to add your LDAP server settings in
 `/etc/gitlab/gitlab.rb` or `/home/git/gitlab/config/gitlab.yml` for Omnibus
@@ -388,7 +389,7 @@ group, you can use the following syntax:
 Find more information about this "LDAP_MATCHING_RULE_IN_CHAIN" filter at
 <https://docs.microsoft.com/en-us/windows/desktop/ADSI/search-filter-syntax>. Support for
 nested members in the user filter should not be confused with
-[group sync nested groups support (EE only)](https://docs.gitlab.com/ee/administration/auth/ldap-ee.html#supported-ldap-group-types-attributes).
+[group sync nested groups support](ldap-ee.md#supported-ldap-group-typesattributes). **[STARTER ONLY]**
 
 Please note that GitLab does not support the custom filter syntax used by
 omniauth-ldap.
diff --git a/doc/administration/auth/smartcard.md b/doc/administration/auth/smartcard.md
new file mode 100644
index 00000000000..b33c5359b44
--- /dev/null
+++ b/doc/administration/auth/smartcard.md
@@ -0,0 +1,186 @@
+# Smartcard authentication **[PREMIUM ONLY]**
+
+GitLab supports authentication using smartcards.
+
+## Authentication methods
+
+GitLab supports two authentication methods:
+
+- X.509 certificates with local databases.
+- LDAP servers.
+
+### Authentication against a local database with X.509 certificates
+
+> [Introduced](https://gitlab.com/gitlab-org/gitlab-ee/issues/726) in
+[GitLab Premium](https://about.gitlab.com/pricing/) 11.6 as an experimental
+feature. Smartcard authentication against local databases may change or be
+removed completely in future releases.
+
+Smartcards with X.509 certificates can be used to authenticate with GitLab.
+
+To use a smartcard with an X.509 certificate to authenticate against a local
+database with GitLab, `CN` and `emailAddress` must be defined in the
+certificate. For example:
+
+```
+Certificate:
+    Data:
+        Version: 1 (0x0)
+        Serial Number: 12856475246677808609 (0xb26b601ecdd555e1)
+    Signature Algorithm: sha256WithRSAEncryption
+        Issuer: O=Random Corp Ltd, CN=Random Corp
+        Validity
+            Not Before: Oct 30 12:00:00 2018 GMT
+            Not After : Oct 30 12:00:00 2019 GMT
+        Subject: CN=Gitlab User, emailAddress=gitlab-user@example.com
+```
+
+### Authentication against an LDAP server
+
+> [Introduced](https://gitlab.com/gitlab-org/gitlab-ee/issues/7693) in
+[GitLab Premium](https://about.gitlab.com/pricing/) 11.8 as an experimental
+feature. Smartcard authentication against an LDAP server may change or be
+removed completely in future releases.
+
+GitLab implements a standard way of certificate matching following
+[RFC4523](https://tools.ietf.org/html/rfc4523). It uses the
+`certificateExactMatch` certificate matching rule against the `userCertificate`
+attribute. As a prerequisite, you must use an LDAP server that:
+
+- Supports the `certificateExactMatch` matching rule.
+- Has the certificate stored in the `userCertificate` attribute.
+
+## Configure GitLab for smartcard authentication
+
+**For Omnibus installations**
+
+1. Edit `/etc/gitlab/gitlab.rb`:
+
+    ```ruby
+    gitlab_rails['smartcard_enabled'] = true
+    gitlab_rails['smartcard_ca_file'] = "/etc/ssl/certs/CA.pem"
+    gitlab_rails['smartcard_client_certificate_required_port'] = 3444
+    ```
+
+1. Save the file and [reconfigure](../restart_gitlab.md#omnibus-gitlab-reconfigure)
+   GitLab for the changes to take effect.
+
+---
+
+**For installations from source**
+
+1. Configure NGINX to request a client side certificate
+
+   In NGINX configuration, an **additional** server context must be defined with
+   the same configuration except:
+
+   - The additional NGINX server context must be configured to run on a different
+     port:
+
+     ```
+     listen *:3444 ssl;
+     ```
+
+   - The additional NGINX server context must be configured to require the client
+     side certificate:
+
+     ```
+     ssl_verify_depth 2;
+     ssl_client_certificate /etc/ssl/certs/CA.pem;
+     ssl_verify_client on;
+     ```
+
+   - The additional NGINX server context must be configured to forward the client
+     side certificate:
+
+     ```
+     proxy_set_header    X-SSL-Client-Certificate    $ssl_client_escaped_cert;
+     ```
+
+   For example, the following is an example server context in an NGINX
+   configuration file (eg. in `/etc/nginx/sites-available/gitlab-ssl`):
+
+   ```
+   server {
+       listen *:3444 ssl;
+
+       # certificate for configuring SSL
+       ssl_certificate /path/to/example.com.crt;
+       ssl_certificate_key /path/to/example.com.key;
+
+       ssl_verify_depth 2;
+       # CA certificate for client side certificate verification
+       ssl_client_certificate /etc/ssl/certs/CA.pem;
+       ssl_verify_client on;
+
+       location / {
+           proxy_set_header    Host                        $http_host;
+           proxy_set_header    X-Real-IP                   $remote_addr;
+           proxy_set_header    X-Forwarded-For             $proxy_add_x_forwarded_for;
+           proxy_set_header    X-Forwarded-Proto           $scheme;
+           proxy_set_header    Upgrade                     $http_upgrade;
+           proxy_set_header    Connection                  $connection_upgrade;
+
+           proxy_set_header    X-SSL-Client-Certificate    $ssl_client_escaped_cert;
+
+           proxy_read_timeout 300;
+
+           proxy_pass http://gitlab-workhorse;
+       }
+   }
+   ```
+
+1. Edit `config/gitlab.yml`:
+
+   ```yaml
+   ## Smartcard authentication settings
+   smartcard:
+     # Allow smartcard authentication
+     enabled: true
+
+     # Path to a file containing a CA certificate
+     ca_file: '/etc/ssl/certs/CA.pem'
+
+     # Port where the client side certificate is requested by NGINX
+     client_certificate_required_port: 3444
+   ```
+
+1. Save the file and [restart](../restart_gitlab.md#installations-from-source)
+   GitLab for the changes to take effect.
+
+### Additional steps when authenticating against an LDAP server
+
+**For Omnibus installations**
+
+1. Edit `/etc/gitlab/gitlab.rb`:
+
+    ```ruby
+    gitlab_rails['ldap_servers'] = YAML.load <<-EOS
+    main:
+      # snip...
+      # Enable smartcard authentication against the LDAP server. Valid values
+      # are "false", "optional", and "required".
+      smartcard_auth: optional
+    EOS
+    ```
+
+1. Save the file and [reconfigure](../restart_gitlab.md#omnibus-gitlab-reconfigure)
+   GitLab for the changes to take effect.
+
+**For installations from source**
+
+1. Edit `config/gitlab.yml`:
+
+    ```yaml
+    production:
+      ldap:
+        servers:
+          main:
+            # snip...
+            # Enable smartcard authentication against the LDAP server. Valid values
+            # are "false", "optional", and "required".
+            smartcard_auth: optional
+    ```
+
+1. Save the file and [restart](../restart_gitlab.md#installations-from-source)
+   GitLab for the changes to take effect.