Chproxy

chproxy

Chproxy 是一个用于 ClickHouse 数据库的 HTTP 代理、负载均衡器。具有以下特性：

• 支持根据输入用户代理请求到多个 ClickHouse 集群。比如，把来自 appserver 的用户请求代理到 stats-raw 集群，把来自 reportserver 用户的请求代理到 stats-aggregate 集群。
• 支持将输入用户映射到每个 ClickHouse 实际用户，这能够防止暴露 ClickHouse 集群的真实用户名称、密码信息。此外，chproxy 还允许映射多个输入用户到某一个单一的 ClickHouse 实际用户。
• 支持接收 HTTP 和 HTTPS 请求。
• 支持通过 IP 或 IP 掩码列表限制 HTTP、HTTPS 访问。
• 支持通过 IP 或 IP 掩码列表限制每个用户的访问。
• 支持限制每个用户的查询时间，通过 KILL QUERY 强制杀执行超时或者被取消的查询。
• 支持限制每个用户的请求频率。
• 支持限制每个用户的请求并发数。
• 所有的限制都可以对每个输入用户、每个集群用户进行设置。
• 支持自动延迟请求，直到满足对用户的限制条件。
• 支持配置每个用户的响应缓存。
• 响应缓存具有内建保护功能，可以防止 惊群效应（thundering herd），即 dogpile 效应。
• 通过 least loaded 和 round robin 技术实现请求在副本和节点间的均衡负载。
• 支持检查节点健康情况，防止向不健康的节点发送请求。
• 通过 Let’s Encrypt 支持 HTTPS 自动签发和更新。
• 可以自行指定选用 HTTP 或 HTTPS 向每个配置的集群代理请求。
• 在将请求代理到 ClickHouse 之前，预先将 User-Agent 请求头与远程/本地地址，和输入/输出的用户名进行关联，因此这些信息可以在 system.query_log.http_user_agent 中查询到。
• 暴露各种有用的符合 Prometheus 内容格式的指标（metrics）。
• 支持配置热更新，配置变更无需重启 —— 只需向 chproxy 进程发送一个 SIGHUP 信号即可。
• 易于管理和运行 —— 只需传递一个配置文件路径给 chproxy 即可。
• 易于配置:

server:
  http:
    listen_addr: ":9090"
    allowed_networks: ["127.0.0.0/24"]

users:
  - name: "default"
    to_cluster: "default"
    to_user: "default"

# by default each cluster has `default` user which can be overridden by section `users`
clusters:
  - name: "default"
    nodes: ["127.0.0.1:8123"]

如何安装

使用预编译的二进制文件

可以从此处下载预编译的 chproxy 二进制文件。

只需要下载最新的稳定版二进制文件，解压使用所需要的配置运行。

./chproxy -config=/path/to/config.yml

从源码进行编译

Chproxy 是基于 Go 开发的，最简单的方式是如下的源编译安装：

go get -u github.com/ContentSquare/chproxy

如果你的系统没有安装 Go，可以参考这个操作指南。

为什么开发了Chproxy

由于各种原因，ClickHouse 的最大执行时间、最大并发语句可能会超过 max_execution_time 和max_concurrent_queries 的限制：

• max_execution_time 可能会因为当前实现的缺陷而被超过。
• max_concurrent_queries 只针对每个节点的限制。如果是在集群节点上，是没法限制集群整体的并发查询数量。

这种 “泄漏” 的限制可能会导致所有集群节点的高资源使用率。遇到这个问题后，我们不得不在我们的 ClickHouse 集群前维护 2 个不同的 http 代理 —— 一个用于在集群节点间分散 INSERT 操作，另一个用于发送 SELECT 到一个专用节点，在该节点再通过某种方式进行限制。这样很不健壮，管理起来也很不方便，所以我们开发了 Chproxy。：）

使用示例

在集群分片间分散 INSERT

通常 INSERT 操作是由有限的几个子网络中的应用服务器发送的，来自其他子网络的 INSERT 操作必须被拒绝。

所有的 INSERT 操作可能会被路由到一个节点上的分布式表，但与其他节点对比，会增加该节点上的资源使用（CPU 和网络资源），因为该节点必须解析每一条被插入的记录，并路由到对应的节点分片。

所以最好是将 INSERT 分散到可用的分片节点上，并将其路由到每个分片表，而不是直接向分布式表进行请求。路由逻辑可以直接嵌入到应用程序生成分散后的 INSERT ，或者通过代理请求的方式。代理请求的方式会更好一些，因为它允许在不修改应用程序配置，对 ClickHouse 集群进行重新配置，避免应用程序的停机时间。多个相同的代理服务可以在不同的服务器上运行，以达到可拓展、高可用的目的。

以下是INSERT分散示例的最小 chproxy 配置：

server:
  http:
      listen_addr: ":9090"

      # Networks with application servers.
      allowed_networks: ["10.10.1.0/24"]

users:
  - name: "insert"
    to_cluster: "stats-raw"
    to_user: "default"

clusters:
  - name: "stats-raw"

    # Requests are spread in `round-robin` + `least-loaded` fashion among nodes.
    # Unreachable and unhealthy nodes are skipped.
    nodes: [
      "10.10.10.1:8123",
      "10.10.10.2:8123",
      "10.10.10.3:8123",
      "10.10.10.4:8123"
    ]

在集群节点间分散来自报表应用的 SELECT

报表应用通常会从 SELECT 查询结果中产生各种用户报表。这些 SELECT 产生的负载在 ClickHouse 集群上可能会有所不同，这取决于在线用户数量和生成的报表类型。很明显，为了防止集群过载，必须限制负载。

所有的 SELECT 可能会被路由到单个节点上的分布式表，该节点会有比其他节点更高的资源使用量（RAM、CPU、网络），因为它必须对从集群其他分片节点获取到数据进行聚合、排序、过滤。

最好是在每个分片节点上创建相同的分布式表，并将 SELECT 分散到所有可用的分片节点上。

以下是SELECT分散示例的最小 chproxy 配置：

server:
  http:
      listen_addr: ":9090"

      # Networks with reporting servers.
      allowed_networks: ["10.10.2.0/24"]

users:
  - name: "report"
    to_cluster: "stats-aggregate"
    to_user: "readonly"
    max_concurrent_queries: 6
    max_execution_time: 1m

clusters:
  - name: "stats-aggregate"
    nodes: [
      "10.10.20.1:8123",
      "10.10.20.2:8123"
    ]
    users:
      - name: "readonly"
        password: "****"

通过 HTTPS 进行用户密码认证

假如你需要设置用户名称/密码用于在任何地方访问 ClickHouse 集群，可能用于在 ClickHouse-grafana 或 Tabix 创建图形界面管理。通过不信任的网络传输为加密的密码和数据，是一个坏主意。因此在这种情况下，必须通过 HTTPS 访问集群。

以下的 chproxy 配置示例演示了 HTTPS 配置：

server:
  https:
    listen_addr: ":443"
    autocert:
      cache_dir: "certs_dir"

users:
  - name: "web"
    password: "****"
    to_cluster: "stats-raw"
    to_user: "web"
    max_concurrent_queries: 2
    max_execution_time: 30s
    requests_per_minute: 10
    deny_http: true

    # Allow `CORS` requests for `tabix`.
    allow_cors: true

    # Enable requests queueing - `chproxy` will queue up to `max_queue_size`
    # of incoming requests for up to `max_queue_time` until they stop exceeding
    # the current limits.
    # This allows gracefully handling request bursts when more than
    # `max_concurrent_queries` concurrent requests arrive.
    max_queue_size: 40
    max_queue_time: 25s

    # Enable response caching. See cache config below.
    cache: "shortterm"

clusters:
  - name: "stats-raw"
    nodes: [
     "10.10.10.1:8123",
     "10.10.10.2:8123",
     "10.10.10.3:8123",
     "10.10.10.4:8123"
    ]
    users:
      - name: "web"
        password: "****"

caches:
  - name: "shortterm"
    dir: "/path/to/cache/dir"
    max_size: 150Mb

    # Cached responses will expire in 130s.
    expire: 130s

以上配置的组合

以上的配置可以通过一个单独的 chproxy config 配置文件进行组合：

server:
  http:
      listen_addr: ":9090"
      allowed_networks: ["10.10.1.0/24","10.10.2.0/24"]
  https:
    listen_addr: ":443"
    autocert:
      cache_dir: "certs_dir"

users:
  - name: "insert"
    allowed_networks: ["10.10.1.0/24"]
    to_cluster: "stats-raw"
    to_user: "default"

  - name: "report"
    allowed_networks: ["10.10.2.0/24"]
    to_cluster: "stats-aggregate"
    to_user: "readonly"
    max_concurrent_queries: 6
    max_execution_time: 1m

  - name: "web"
    password: "****"
    to_cluster: "stats-raw"
    to_user: "web"
    max_concurrent_queries: 2
    max_execution_time: 30s
    requests_per_minute: 10
    deny_http: true
    allow_cors: true
    max_queue_size: 40
    max_queue_time: 25s
    cache: "shortterm"

clusters:
  - name: "stats-aggregate"
    nodes: [
      "10.10.20.1:8123",
      "10.10.20.2:8123"
    ]
    users:
    - name: "readonly"
      password: "****"

  - name: "stats-raw"
    nodes: [
     "10.10.10.1:8123",
     "10.10.10.2:8123",
     "10.10.10.3:8123",
     "10.10.10.4:8123"
    ]
    users:
      - name: "default"

      - name: "web"
        password: "****"

caches:
  - name: "shortterm"
    dir: "/path/to/cache/dir"
    max_size: 150Mb
    expire: 130s

配置

服务配置

Chproxy 可以接收 HTTP 和 HTTPS 协议的请求。其中 HTTPS 必须使用自定义证书或自动 Let’s Encrypt 证书进行配置。

可以通过 IP 列表或 IP 掩码进行限制对 chproxy 的访问进行限制。这个选项可以应用于 HTTP, HTTPS, metrics, user 或 cluster-user 配置。

用户配置

有两种类型的用户： in-users (在全局部分) 和 out-users (在集群部分)。

所有的请求都会匹配到 in-users ，如果所有检查通过，将会被覆盖凭证后匹配到 out-users。

假设我们有一个只读权限 read-only 的 ClickHouse 用户 web ，和 max_concurrent_queries: 4 的最高并发限制。

有两个不同的应用程序从 ClickHouse 读取，我们可以创建两个不同的 in-users ，对应的 to_user 为 “web”，同时为每一个都设置 max_concurrent_queries: 2，以避免任意一个应用用尽所有 web 用户的 4 并发请求限制。

对 chproxy的请求必须通过 user_config 配置中的用户凭证认证，凭证信息可以通过 BasicAuth 或用户名/密码的查询字符串参数来传递。

对于 in-users 和 out-users 的限制是相互独立的。

集群配置

Chproxy 可以配置多个逻辑集群 cluster，每个逻辑集群必须包含一个名称和节点列表、或者副本节点列表。请参考 cluster-config 了解更详细的内容。

对集群节点、副本节点之间的请求采用的是 round-robin + least-loaded 的均衡方式。

如果在近期对某个节点请求不成功，该节点在很短的时间间隔内优先度会被自动降低。这意味着 chproxy 在每次请求中，会自动选择副本负载最小的健康节点。

此外，每个节点都会定期检查可用性。不可用的节点会被自动从逻辑集群中排除，直到它们再次可用为止。这允许在不从实际的 ClickHouse 集群中删除不可用节点的情况下，进行节点维护。

Chproxy 会自动杀死超过 max_execution_time 限制的查询。默认情况下，chproxy 会尝试杀死 default 用户下的这些超时查询，可以通过 kill_query_user 来覆盖该用户设置。

如果没有指定逻辑集群的用户配置部分，会默认使用 default 用户。

缓存配置

Chproxy 支持配置响应缓存。可以创建多个 cache-configs 中的各项细节配置。

通过给用户指定缓存名称，可以启用响应缓存。多个用户可以共享同一个缓存。

目前只有 SELECT 响应会被缓存。

对于请求字符串中设置了 no_cache=1 的请求，缓存会被禁用。

可以在查询字符串中传递可选的缓存命名空间，如 cache_namespace=aaaa 。这允许缓存在不同命名空间下对相同的查询做出不同的响应。此外，可以在缓存空间上建立即时缓存刷新 —— 只需按照顺序切换到新的命名空间，即可刷新缓存。

安全配置

Chproxy 可以在将请求代理到 ClickHouse 集群前，自定义从输入请求中删除查询参数（除了这里列出的用户参数 和这些参数）。这可以防止请求不安全地覆盖各种 ClickHouse 设置。

在设置限制时候需要小心，比如允许网络、密码等。

默认情况下，chproxy 会尝试检测最明显的安全配置问题时，如 allowed_networks: ["0.0.0.0/0"] ，或未加密的 HTTP 发送密码行为。

特殊选项 hack_me_please: true 可以用于禁用 chproxy 对配置的安全相关检查。（如果你感觉良好 ：））

完整配置示例

# Whether to print debug logs.
#
# By default debug logs are disabled.
log_debug: true

# Whether to ignore security checks during config parsing.
#
# By default security checks are enabled.
hack_me_please: true

# Optional response cache configs.
#
# Multiple distinct caches with different settings may be configured.
caches:
    # Cache name, which may be passed into `cache` option on the `user` level.
    #
    # Multiple users may share the same cache.
  - name: "longterm"

    # Path to directory where cached responses will be stored.
    dir: "/path/to/longterm/cachedir"

    # Maximum cache size.
    # `Kb`, `Mb`, `Gb` and `Tb` suffixes may be used.
    max_size: 100Gb

    # Expiration time for cached responses.
    expire: 1h

    # When multiple requests with identical query simultaneously hit `chproxy`
    # and there is no cached response for the query, then only a single
    # request will be proxied to clickhouse. Other requests will wait
    # for the cached response during this grace duration.
    # This is known as protection from `thundering herd` problem.
    #
    # By default `grace_time` is 5s. Negative value disables the protection
    # from `thundering herd` problem.
    grace_time: 20s

  - name: "shortterm"
    dir: "/path/to/shortterm/cachedir"
    max_size: 100Mb
    expire: 10s

# Optional network lists, might be used as values for `allowed_networks`.
network_groups:
  - name: "office"
    # Each item may contain either IP or IP subnet mask.
    networks: ["127.0.0.0/24", "10.10.0.1"]

  - name: "reporting-apps"
    networks: ["10.10.10.0/24"]

# Optional lists of query params to send with each proxied request to ClickHouse.
# These lists may be used for overriding ClickHouse settings on a per-user basis.
param_groups:
    # Group name, which may be passed into `params` option on the `user` level.
  - name: "cron-job"
    # List of key-value params to send
    params:
      - key: "max_memory_usage"
        value: "40000000000"

      - key: "max_bytes_before_external_group_by"
        value: "20000000000"

  - name: "web"
    params:
      - key: "max_memory_usage"
        value: "5000000000"

      - key: "max_columns_to_read"
        value: "30"

      - key: "max_execution_time"
        value: "30"

# Settings for `chproxy` input interfaces.
server:
  # Configs for input http interface.
  # The interface works only if this section is present.
  http:
    # TCP address to listen to for http.
    # May be in the form IP:port . IP part is optional.
    listen_addr: ":9090"

    # List of allowed networks or network_groups.
    # Each item may contain IP address, IP subnet mask or a name
    # from `network_groups`.
    # By default requests are accepted from all the IPs.
    allowed_networks: ["office", "reporting-apps", "1.2.3.4"]

    # ReadTimeout is the maximum duration for proxy to reading the entire
    # request, including the body.
    # Default value is 1m
    read_timeout: 5m

    # WriteTimeout is the maximum duration for proxy before timing out writes of the response.
    # Default is largest MaxExecutionTime + MaxQueueTime value from Users or Clusters
    write_timeout: 10m

    # IdleTimeout is the maximum amount of time for proxy to wait for the next request.
    # Default is 10m
    idle_timeout: 20m

  # Configs for input https interface.
  # The interface works only if this section is present.
  https:
    # TCP address to listen to for https.
    listen_addr: ":443"

    # Paths to TLS cert and key files.
    # If you change the cert & key files while chproxy is running, you have to restart chproxy so that it loads them.
    # Triggering a SIGHUP signal won't work as for the rest of the configuration.
    # cert_file: "cert_file"
    # key_file: "key_file"

    # Letsencrypt config.
    # Certificates are automatically issued and renewed if this section
    # is present.
    # There is no need in cert_file and key_file if this section is present.
    # Autocert requires application to listen on :80 port for certificate generation
    autocert:
      # Path to the directory where autocert certs are cached.
      cache_dir: "certs_dir"

      # The list of host names proxy is allowed to respond to.
      # See https://godoc.org/golang.org/x/crypto/acme/autocert#HostPolicy
      allowed_hosts: ["example.com"]

  # Metrics in prometheus format are exposed on the `/metrics` path.
  # Access to `/metrics` endpoint may be restricted in this section.
  # By default access to `/metrics` is unrestricted.
  metrics:
    allowed_networks: ["office"]

# Configs for input users.
users:
    # Name and password are used to authorize access via BasicAuth or
    # via `user`/`password` query params.
    # Password is optional. By default empty password is used.
  - name: "web"
    password: "****"

    # Requests from the user are routed to this cluster.
    to_cluster: "first cluster"

    # Input user is substituted by the given output user from `to_cluster`
    # before proxying the request.
    to_user: "web"

    # Whether to deny input requests over HTTP.
    deny_http: true

    # Whether to allow `CORS` requests like `tabix` does.
    # By default `CORS` requests are denied for security reasons.
    allow_cors: true

    # Requests per minute limit for the given input user.
    #
    # By default there is no per-minute limit.
    requests_per_minute: 4

    # Response cache config name to use.
    #
    # By default responses aren't cached.
    cache: "longterm"

    # An optional group of params to send to ClickHouse with each proxied request.
    # These params may be set in param_groups block.
    #
    # By default no additional params are sent to ClickHouse.
    params: "web"

    # The maximum number of requests that may wait for their chance
    # to be executed because they cannot run now due to the current limits.
    #
    # This option may be useful for handling request bursts from `tabix`
    # or `clickhouse-grafana`.
    #
    # By default all the requests are immediately executed without
    # waiting in the queue.
    max_queue_size: 100

    # The maximum duration the queued requests may wait for their chance
    # to be executed.
    # This option makes sense only if max_queue_size is set.
    # By default requests wait for up to 10 seconds in the queue.
    max_queue_time: 35s

  - name: "default"
    to_cluster: "second cluster"
    to_user: "default"
    allowed_networks: ["office", "1.2.3.0/24"]

    # The maximum number of concurrently running queries for the user.
    #
    # By default there is no limit on the number of concurrently
    # running queries.
    max_concurrent_queries: 4

    # The maximum query duration for the user.
    # Timed out queries are forcibly killed via `KILL QUERY`.
    #
    # By default set to 120s.
    max_execution_time: 1m

    # Whether to deny input requests over HTTPS.
    deny_https: true

# Configs for ClickHouse clusters.
clusters:
    # The cluster name is used in `to_cluster`.
  - name: "first cluster"

    # Protocol to use for communicating with cluster nodes.
    # Currently supported values are `http` or `https`.
    # By default `http` is used.
    scheme: "http"

    # Cluster node addresses.
    # Requests are evenly distributed among them.
    nodes: ["127.0.0.1:8123", "shard2:8123"]

    # User configuration for heart beat requests.
    # Credentials of the first user in clusters.users will be used for heart beat requests to clickhouse.
    heartbeat:
      # An interval for checking all cluster nodes for availability
      # By default each node is checked for every 5 seconds.
      interval: 1m

      # A timeout of wait response from cluster nodes
      # By default 3s
      timeout: 10s

      # The parameter to set the URI to request in a health check
      # By default "/?query=SELECT%201"
      request: "/?query=SELECT%201%2B1"

      # Reference response from clickhouse on health check request
      # By default "1\n"
      response: "2\n"

    # Timed out queries are killed using this user.
    # By default `default` user is used.
    kill_query_user:
      name: "default"
      password: "***"

    # Configuration for cluster users.
    users:
        # The user name is used in `to_user`.
      - name: "web"
        password: "password"
        max_concurrent_queries: 4
        max_execution_time: 1m

  - name: "second cluster"
    scheme: "https"

    # The cluster may contain multiple replicas instead of flat nodes.
    #
    # Chproxy selects the least loaded node among the least loaded replicas.
    replicas:
      - name: "replica1"
        nodes: ["127.0.1.1:8443", "127.0.1.2:8443"]
      - name: "replica2"
        nodes: ["127.0.2.1:8443", "127.0.2.2:8443"]

    users:
      - name: "default"
        max_concurrent_queries: 4
        max_execution_time: 1m

      - name: "web"
        max_concurrent_queries: 4
        max_execution_time: 10s
        requests_per_minute: 10
        max_queue_size: 50
        max_queue_time: 70s
        allowed_networks: ["office"]

完整的配置规范请参考这里

指标

所有的指标都以 Prometheus 文本格式暴露在 /metrics 路径上。

Name	Type	Description	Labels
bad_requests_total	Counter	The number of unsupported requests
cache_hits_total	Counter	The amount of cache hits	cache, user, cluster, cluster_user
cache_items	Gauge	The number of items in each cache	cache
cache_miss_total	Counter	The amount of cache misses	cache, user, cluster, cluster_user
cache_size	Gauge	Size of each cache	cache
cached_response_duration_seconds	Summary	Duration for cached responses. Includes the duration for sending response to client	cache, user, cluster, cluster_user
canceled_request_total	Counter	The number of requests canceled by remote client	user, cluster, cluster_user, replica, cluster_node
cluster_user_queue_overflow_total	Counter	The number of overflows for per-cluster_user request queues	user, cluster, cluster_user
concurrent_limit_excess_total	Counter	The number of rejected requests due to max_concurrent_queries limit	user, cluster, cluster_user, replica, cluster_node
concurrent_queries	Gauge	The number of concurrent queries at the moment	user, cluster, cluster_user, replica, cluster_node
config_last_reload_successful	Gauge	Whether the last configuration reload attempt was successful
config_last_reload_success_timestamp_seconds	Gauge	Timestamp of the last successful configuration reload
host_health	Gauge	Health state of hosts by clusters	cluster, replica, cluster_node
host_penalties_total	Counter	The number of given penalties by host	cluster, replica, cluster_node
killed_request_total	Counter	The number of requests killed by proxy	user, cluster, cluster_user, replica, cluster_node
proxied_response_duration_seconds	Summary	Duration for responses proxied from ClickHouse	user, cluster, cluster_user, replica, cluster_node
request_body_bytes_total	Counter	The amount of bytes read from request bodies	user, cluster, cluster_user, replica, cluster_node
request_duration_seconds	Summary	Request duration. Includes possible queue wait time	user, cluster, cluster_user, replica, cluster_node
request_queue_size	Gauge	Request queue size at the moment	user, cluster, cluster_user
request_success_total	Counter	The number of successfully proxied requests	user, cluster, cluster_user, replica, cluster_node
request_sum_total	Counter	The number of processed requests	user, cluster, cluster_user, replica, cluster_node
response_body_bytes_total	Counter	The amount of bytes written to response bodies	user, cluster, cluster_user, replica, cluster_node
status_codes_total	Counter	Distribution by response status codes	user, cluster, cluster_user, replica, cluster_node, code
timeout_request_total	Counter	The number of timed out requests	user, cluster, cluster_user, replica, cluster_node
user_queue_overflow_total	Counter	The number of overflows for per-user request queues	user, cluster, cluster_user

这里与一个 Grafana 的 chproxy 指标仪表盘例子。

FAQ

• chproxy 是否可用于生产环境？

是的，我们生产环境中将它成功用于 INSERT 和 SELECT 请求。

• chproxy 性能表现怎么样？

  在我们的生产环境中，单个 chproxy 实例可以在使用不到 20% 的单 CPU 核心资源情况下，轻松代理 1Gbps 的压缩 INSERT 数据。

• chproxy 是否支持 ClickHouse 的 Native 协议？

不支持，应为我们所有的所有的应用只通过 HTTP 协议与 ClickHouse 通讯。

可能会在未来增加对 Native 协议的支持。