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https://github.com/gravitational/teleport
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8356ae6a74
This commit expands the usage of the caching layer for auth server API: * Introduces in-memory cache that is used to serve all Auth server API requests. This is done to achieve scalability on 10K+ node clusters, where each node fetches certificate authorities, roles, users and join tokens. It is not possible to scale DynamoDB backend or other backends on 10K reads per seconds on a single shard or partition. The solution is to introduce an in-memory cache of the backend state that is always used for reads. * In-memory cache has been expanded to support all resources required by the auth server. * Experimental `tctl top` command has been introduced to display common single node metrics. Replace SQLite Memory Backend with BTree SQLite in memory backend was suffering from high tail latencies under load (up to 8 seconds in 99.9%-ile on load configurations). This commit replaces the SQLite memory caching backend with in-memory BTree backend that brought down tail latencies to 2 seconds (99.9%-ile) and brought overall performance improvement.
33 lines
1.1 KiB
Go
33 lines
1.1 KiB
Go
/*
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Copyright 2018-2019 Gravitational, Inc.
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Licensed under the Apache License, Version 2.0 (the "License");
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you may not use this file except in compliance with the License.
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You may obtain a copy of the License at
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http://www.apache.org/licenses/LICENSE-2.0
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Unless required by applicable law or agreed to in writing, software
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distributed under the License is distributed on an "AS IS" BASIS,
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WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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See the License for the specific language governing permissions and
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limitations under the License.
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*/
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// Package cache implements event-driven cache layer
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// that is used by auth servers, proxies and nodes.
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//
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// The cache fetches resources and then subscribes
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// to the events watcher to receive updates.
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//
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// This approach allows cache to be up to date without
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// time based expiration and avoid re-fetching all
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// resources reducing bandwitdh.
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//
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// There are two types of cache backends used:
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//
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// * SQLite-based in-memory used for auth nodes
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// * SQLite-based on disk persistent cache for nodes and proxies
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// providing resilliency in the face of auth servers failures.
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package cache
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