mirror of https://github.com/status-im/consul.git
281 lines
11 KiB
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281 lines
11 KiB
Plaintext
---
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layout: docs
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page_title: Connect - Deprecated Managed Proxies
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description: |-
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Consul 1.2 launched its Connect Beta period with a feature named Managed
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Proxies which are now deprecated. This page describes how they worked and why
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they are no longer supported.
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---
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# Managed Proxy Deprecation
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Consul Connect was first released as a beta feature in Consul 1.2.0. The initial
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release included a feature called "Managed Proxies". Managed proxies were
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Connect proxies where the proxy process was started, configured, and stopped by
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Consul. They were enabled via basic configurations within the service
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definition.
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!> **Consul 1.6.0 removes Managed Proxies completely.**
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This documentation is provided for prior versions only. You may consider using
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[sidecar service
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registrations](/docs/connect/registration/sidecar-service) instead.
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Managed proxies have been deprecated since Consul 1.3 and have been fully removed
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in Consul 1.6. Anyone using Managed Proxies should aim to change their workflow
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as soon as possible to avoid issues with a later upgrade.
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After transitioning away from all managed proxy usage, the `proxy` subdirectory inside [`data_dir`](/docs/agent/config/cli-flags#_data_dir) (specified in Consul config) can be deleted to remove extraneous configuration files and free up disk space.
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**new and known issues will not be fixed**.
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## Deprecation Rationale
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Originally managed proxies traded higher implementation complexity for an easier
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"getting started" user experience. After seeing how Connect was investigated and
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adopted during beta it became obvious that they were not the best trade off.
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Managed proxies only really helped in local testing or VM-per-service based
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models whereas a lot of users jumped straight to containers where they are not
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helpful. They also add only targeted fairly basic supervisor features which
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meant most people would want to use something else in production for consistency
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with other workloads. So the high implementation cost of building robust process
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supervision didn't actually benefit most real use-cases.
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Instead of this Connect 1.3.0 introduces the concept of [sidecar service
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registrations](/docs/connect/registration/sidecar-service) which
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have almost all of the benefits of simpler configuration but without any of the
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additional process management complexity. As a result they can be used to
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simplify configuration in both container-based and realistic production
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supervisor settings.
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## Managed Proxy Documentation
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As the managed proxy features continue to be supported for now, the rest of this
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page will document how they work in the interim.
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-> **Deprecation Note:** It's _strongly_ recommended you do not build anything
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using Managed proxies and consider using [sidecar service
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registrations](/docs/connect/registration/sidecar-service) instead.
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Managed proxies are given
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a unique proxy-specific ACL token that allows read-only access to Connect
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information for the specific service the proxy is representing. This ACL
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token is more restrictive than can be currently expressed manually in
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an ACL policy.
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The default managed proxy is a basic proxy built-in to Consul and written
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in Go. Having a basic built-in proxy allows Consul to have a reasonable default
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with performance that is good enough for most workloads. In some basic
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benchmarks, the service-to-service communication over the built-in proxy
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could sustain 5 Gbps with sub-millisecond latency. Therefore,
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the performance impact of even the basic built-in proxy is minimal.
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Consul will be integrating with advanced proxies in the near future to support
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more complex configurations and higher performance. The configuration below is
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all for the built-in proxy.
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-> **Security Note:** 1.) Managed proxies can only be configured
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via agent configuration files. They _cannot_ be registered via the HTTP API.
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And 2.) Managed proxies are not started at all if Consul is running as root.
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Both of these default configurations help prevent arbitrary process
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execution or privilege escalation. This behavior can be configured
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[per-agent](/docs/agent/config).
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### Lifecycle
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The Consul agent starts managed proxies on demand and supervises them,
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restarting them if they crash. The lifecycle of the proxy process is decoupled
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from the agent so if the agent crashes or is restarted for an upgrade, the
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managed proxy instances will _not_ be stopped.
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Note that this behavior while desirable in production might leave proxy
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processes running indefinitely if you manually stop the agent and clear its
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data dir during testing.
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To terminate a managed proxy cleanly you need to deregister the service that
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requested it. If the agent is already stopped and will not be restarted again,
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you may choose to locate the proxy processes and kill them manually.
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While in `-dev` mode, unless a `-data-dir` is explicitly set, managed proxies
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switch to being killed when the agent exits since it can't store state in order
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to re-adopt them on restart.
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### Minimal Configuration
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Managed proxies are configured within a
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[service definition](/docs/discovery/services). The simplest possible
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managed proxy configuration is an empty configuration. This enables the
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default managed proxy and starts a listener for that service:
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```json
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{
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"service": {
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"name": "redis",
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"port": 6379,
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"connect": { "proxy": {} }
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}
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}
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```
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The listener is started on random port within the configured Connect
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port range. It can be discovered using the
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[DNS interface](/docs/discovery/dns#connect-capable-service-lookups)
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or
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[Catalog API](#).
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In most cases, service-to-service communication is established by
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a proxy configured with upstreams (described below), which handle the
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discovery transparently.
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### Upstream Configuration
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To transparently discover and establish Connect-based connections to
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dependencies, they must be configured with a static port on the managed
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proxy configuration:
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```json
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{
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"service": {
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"name": "web",
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"port": 8080,
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"connect": {
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"proxy": {
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"upstreams": [
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{
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"destination_name": "redis",
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"local_bind_port": 1234
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}
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]
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}
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}
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}
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}
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```
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In the example above,
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"redis" is configured as an upstream with static port 1234 for service "web".
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When a TCP connection is established on port 1234, the proxy
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will find Connect-compatible "redis" services via Consul service discovery
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and establish a TLS connection identifying as "web".
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~> **Security:** Any application that can communicate to the configured
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static port will be able to masquerade as the source service ("web" in the
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example above). You must either trust any loopback access on that port or
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use namespacing techniques provided by your operating system.
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-> **Deprecation Note:** versions 1.2.0 to 1.3.0 required specifying `upstreams`
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as part of the opaque `config` that is passed to the proxy. However, since
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1.3.0, the `upstreams` configuration is now specified directly under the
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`proxy` key. Old service definitions using the nested config will continue to
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work and have the values copied into the new location. This allows the upstreams
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to be registered centrally rather than being part of the local-only config
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passed to the proxy instance.
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For full details of the additional configurable options available when using the
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built-in proxy see the [built-in proxy configuration
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reference](/docs/connect/configuration).
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### Prepared Query Upstreams
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The upstream destination may also be a
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[prepared query](/api-docs/query).
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This allows complex service discovery behavior such as connecting to
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the nearest neighbor or filtering by tags.
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For example, given a prepared query named "nearest-redis" that is
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configured to route to the nearest Redis instance, an upstream can be
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configured to route to this query. In the example below, any TCP connection
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to port 1234 will attempt a Connect-based connection to the nearest Redis
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service.
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```json
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{
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"service": {
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"name": "web",
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"port": 8080,
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"connect": {
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"proxy": {
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"upstreams": [
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{
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"destination_name": "redis",
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"destination_type": "prepared_query",
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"local_bind_port": 1234
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}
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]
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}
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}
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}
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}
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```
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For full details of the additional configurable options available when using the
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built-in proxy see the [built-in proxy configuration
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reference](/docs/connect/configuration).
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### Custom Managed Proxy
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[Custom proxies](/docs/connect/proxies/integrate) can also be
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configured to run as a managed proxy. To configure custom proxies, specify
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an alternate command to execute for the proxy:
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```json
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{
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"service": {
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"name": "web",
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"port": 8080,
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"connect": {
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"proxy": {
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"exec_mode": "daemon",
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"command": ["/usr/bin/my-proxy", "-flag-example"],
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"config": {
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"foo": "bar"
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}
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}
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}
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}
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}
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```
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The `exec_mode` value specifies how the proxy is executed. The only
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supported value at this time is "daemon". The command is the binary and
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any arguments to execute.
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The "daemon" mode expects a proxy to run as a long-running, blocking
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process. It should not double-fork into the background. The custom
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proxy should retrieve its configuration (such as the port to run on)
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via the [custom proxy integration APIs](/docs/connect/proxies/integrate).
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The default proxy command can be changed at an agent-global level
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in the agent configuration. An example in HCL format is shown below.
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```
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connect {
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proxy_defaults {
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command = ["/usr/bin/my-proxy"]
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}
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}
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```
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With this configuration, all services registered without an explicit
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proxy command will use `my-proxy` instead of the default built-in proxy.
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The `config` key is an optional opaque JSON object which will be passed through
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to the proxy via the proxy configuration endpoint to allow any configuration
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options the proxy needs to be specified. See the [built-in proxy
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configuration reference](/docs/connect/configuration)
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for details of config options that can be passed when using the built-in proxy.
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### Managed Proxy Logs
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Managed proxies have both stdout and stderr captured in log files in the agent's
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`data_dir`. They can be found in
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`<data_dir>/proxy/logs/<proxy_service_id>-std{err,out}.log`.
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The built-in proxy will inherit its log level from the agent so if the agent is
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configured with `log_level = DEBUG`, a proxy it starts will also output `DEBUG`
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level logs showing service discovery, certificate and authorization information.
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~> **Note:** In `-dev` mode there is no `data_dir` unless one is explicitly
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configured so logging is disabled. You can access logs by providing the
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[`-data-dir`](/docs/agent/config/cli-flags#_data_dir) CLI option. If a data dir is
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configured, this will also cause proxy processes to stay running when the agent
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terminates as described in [Lifecycle](#lifecycle).
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