Remove Git circuit breaker

Was introduced in the time that GitLab still used NFS, which is not
required anymore in most cases. By removing this, the API it calls will
return empty responses. This interface has to be removed in the next
major release, expected to be 12.0.

6 files changed, 3 insertions, 129 deletions

diff --git a/doc/administration/img/circuitbreaker_config.png b/doc/administration/img/circuitbreaker_config.png
deleted file mode 100644
index 20233276055..00000000000
--- a/doc/administration/img/circuitbreaker_config.png
+++ /dev/null
diff --git a/doc/administration/img/failing_storage.png b/doc/administration/img/failing_storage.png
deleted file mode 100644
index 652d7dcb5d7..00000000000
--- a/doc/administration/img/failing_storage.png
+++ /dev/null
diff --git a/doc/administration/monitoring/prometheus/gitlab_metrics.md b/doc/administration/monitoring/prometheus/gitlab_metrics.md
index 7bc92ae77ee..c6fd7ef7360 100644
--- a/doc/administration/monitoring/prometheus/gitlab_metrics.md
+++ b/doc/administration/monitoring/prometheus/gitlab_metrics.md
@@ -45,9 +45,6 @@ The following metrics are available:
 | redis_ping_success                | Gauge     | 9.4   | Whether or not the last redis ping succeeded |
 | redis_ping_latency_seconds        | Gauge     | 9.4   | Round trip time of the redis ping |
 | user_session_logins_total         | Counter   | 9.4   | Counter of how many users have logged in |
-| filesystem_circuitbreaker_latency_seconds | Gauge | 9.5 | Time spent validating if a storage is accessible |
-| filesystem_circuitbreaker         | Gauge     | 9.5   | Whether or not the circuit for a certain shard is broken or not |
-| circuitbreaker_storage_check_duration_seconds | Histogram | 10.3 | Time a single storage probe took |
 | failed_login_captcha_total        | Gauge | 11.0 | Counter of failed CAPTCHA attempts during login |
 | successful_login_captcha_total    | Gauge | 11.0 | Counter of successful CAPTCHA attempts during login |
 
diff --git a/doc/administration/repository_storage_paths.md b/doc/administration/repository_storage_paths.md
index 7ea7ed48850..c03f23a8931 100644
--- a/doc/administration/repository_storage_paths.md
+++ b/doc/administration/repository_storage_paths.md
@@ -97,55 +97,6 @@ be stored via the **Application Settings** in the Admin area.
 Beginning with GitLab 8.13.4, multiple paths can be chosen. New projects will be
 randomly placed on one of the selected paths.
 
-## Handling failing repository storage
-
-> [Introduced][ce-11449] in GitLab 9.5.
-
-When GitLab detects access to the repositories storage fails repeatedly, it can
-gracefully prevent attempts to access the storage. This might be useful when
-the repositories are stored somewhere on the network.
-
-This can be configured from the admin interface:
-
-![circuitbreaker configuration](img/circuitbreaker_config.png)
-
-**Number of access attempts**: The number of attempts GitLab will make to access a
-storage when probing a shard.
-
-**Number of failures before backing off**: The number of failures after which
-GitLab will start temporarily disabling access to a storage shard on a host.
-
-**Maximum git storage failures:** The number of failures of after which GitLab will
-completely prevent access to the storage. The number of failures can be reset in
-the admin interface: `https://gitlab.example.com/admin/health_check` or using the
-[api](../api/repository_storage_health.md) to allow access to the storage again.
-
-**Seconds to wait after a storage failure:** When access to a storage fails. GitLab
-will prevent access to the storage for the time specified here. This allows the
-filesystem to recover.
-
-**Seconds before reseting failure information:** The time in seconds GitLab will
-keep failure information. When no failures occur during this time, information about the
-mount is reset.
-
-**Seconds to wait for a storage access attempt:** The time in seconds GitLab will
-try to access storage. After this time a timeout error will be raised.
-
-To enable the circuitbreaker for repository storage you can flip the feature flag from a rails console:
-
-```
-Feature.enable('git_storage_circuit_breaker')
-```
-
-Alternatively it can be enabled by setting `true` in the `GIT_STORAGE_CIRCUIT_BREAKER` environment variable.
-This approach would be used when enabling the circuit breaker on a single host.
-
-When storage failures occur, this will be visible in the admin interface like this:
-
-![failing storage](img/failing_storage.png)
-
-To allow access to all storages, click the `Reset git storage health information` button.
-
 [ce-4578]: https://gitlab.com/gitlab-org/gitlab-ce/merge_requests/4578
 [restart-gitlab]: restart_gitlab.md#installations-from-source
 [reconfigure-gitlab]: restart_gitlab.md#omnibus-gitlab-reconfigure
diff --git a/doc/api/repository_storage_health.md b/doc/api/repository_storage_health.md
index e0c0315c2d7..edf4b04acea 100644
--- a/doc/api/repository_storage_health.md
+++ b/doc/api/repository_storage_health.md
@@ -1,74 +1,5 @@
 # Circuitbreaker API
 
-> [Introduced][ce-11449] in GitLab 9.5.
-
-The Circuitbreaker API is only accessible to administrators. All requests by
-guests will respond with `401 Unauthorized`, and all requests by normal users
-will respond with `403 Forbidden`.
-
-## Repository Storages
-
-### Get all storage information
-
-Returns of all currently configured storages and their health information.
-
-```
-GET /circuit_breakers/repository_storage
-```
-
-```bash
-curl --header "PRIVATE-TOKEN: 9koXpg98eAheJpvBs5tK" https://gitlab.example.com/api/v4/circuit_breakers/repository_storage
-```
-
-```json
-[
-  {
-    "storage_name": "default",
-    "failing_on_hosts": [],
-    "total_failures": 0
-  },
-  {
-    "storage_name": "broken",
-    "failing_on_hosts": [
-      "web01", "worker01"
-    ],
-    "total_failures": 1
-  }
-]
-```
-
-### Get failing storages
-
-This returns a list of all currently failing storages.
-
-```
-GET /circuit_breakers/repository_storage/failing
-```
-
-```bash
-curl --header "PRIVATE-TOKEN: 9koXpg98eAheJpvBs5tK" https://gitlab.example.com/api/v4/circuit_breakers/repository_storage/failing
-```
-
-```json
-[
-    {
-        "storage_name":"broken",
-        "failing_on_hosts":["web01", "worker01"],
-        "total_failures":2
-    }
-]
-```
-
-## Reset failing storage information
-
-Use this remove all failing storage information and allow access to the storage again.
-
-```
-DELETE /circuit_breakers/repository_storage
-```
-
-```bash
-curl --request DELETE --header "PRIVATE-TOKEN: 9koXpg98eAheJpvBs5tK" https://gitlab.example.com/api/v4/circuit_breakers/repository_storage
-```
-
-[ce-11449]: https://gitlab.com/gitlab-org/gitlab-ce/merge_requests/11449
+NOTE: **Deprecated:**
+Support of the circuit breaker is removed, as Gitaly can be configured to 
+to work without NFS and [communicate solely over HTTP](../administration/gitaly/index.md).
diff --git a/doc/api/settings.md b/doc/api/settings.md
index 1c41b3345ad..4482030888d 100644
--- a/doc/api/settings.md
+++ b/doc/api/settings.md
@@ -138,11 +138,6 @@ are listed in the descriptions of the relevant settings.
 | `authorized_keys_enabled`                | boolean          | no                                   | By default, we write to the `authorized_keys` file to support Git over SSH without additional configuration. GitLab can be optimized to authenticate SSH keys via the database file. Only disable this if you have configured your OpenSSH server to use the AuthorizedKeysCommand. |
 | `auto_devops_domain`                     | string           | no                                   | Specify a domain to use by default for every project's Auto Review Apps and Auto Deploy stages. |
 | `auto_devops_enabled`                    | boolean          | no                                   | Enable Auto DevOps for projects by default. It will automatically build, test, and deploy applications based on a predefined CI/CD configuration. |
-| `circuitbreaker_access_retries`          | integer          | no                                   | The number of attempts GitLab will make to access a storage. |
-| `circuitbreaker_check_interval`          | integer          | no                                   | Number of seconds in between storage checks. |
-| `circuitbreaker_failure_count_threshold` | integer          | no                                   | The number of failures after which GitLab will completely prevent access to the storage.  |
-| `circuitbreaker_failure_reset_time`      | integer          | no                                   | Time in seconds GitLab will keep storage failure information. When no failures occur during this time, the failure information is reset. |
-| `circuitbreaker_storage_timeout`         | integer          | no                                   | Seconds to wait for a storage access attempt. |
 | `clientside_sentry_dsn`                  | string           | required by: `clientside_sentry_enabled` | Clientside Sentry Data Source Name. |
 | `clientside_sentry_enabled`              | boolean          | no                                   | (**If enabled, requires:** `clientside_sentry_dsn`) Enable Sentry error reporting for the client side. |
 | `container_registry_token_expire_delay`  | integer          | no                                   | Container Registry token duration in minutes. |