152 lines
5.5 KiB
Markdown
152 lines
5.5 KiB
Markdown
---
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title: Edge Cluster
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sidebar_label: Edge Cluster
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hide_title: false
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hide_table_of_contents: false
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---
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# Edge Server
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SRS edge dedicates to support huge players for a small set of streams.
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Note: The edge server need to serve many clients, the SRS performance is ok.
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Use Scenarios for Edge:
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* CDN/VDN RTMP cluster, for many clients to upload(publish) or download(play).
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* Small cluster, but many clients to publish. Forward is not ok for all stream is forwarded,
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while edge is ok for it only fetch when user play the specified stream.
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* The BGP server is costly, while the edge is cheap. Use multiple levels edge
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to ensure the BGP server low bandwidth.
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Note: Edge can fetch stream from or push stream to origin. When user play
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a stream on edge, edge will fetch from origin. When user publish stream to
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edge, edge will push to origin.
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Note: Always use Edge, except you actually know the forward. The forward will
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always forward stream to multiple servers; while the edge only fetch or push
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stream to a server and switch to next when error.
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## Concepts
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When a vhost set mode to remote, the vhost in server is edge.
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When a vhost set mode to local, the vhost in server is origin.
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Edge is used to cache the stream of origin.
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When user publish stream to the edge server, edge will forward the stream
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to origin. For example, the origin server is in beijing, a user at shanghai needs
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to pubish stream to origin server, we can add a edge server at shanghai, when
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user publish stream to shanghai edge server, the edge server will forward stream to
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beijing.
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When user play the stream on edge, edge will fetch from origin when it has not
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cache it yet. When edge already cached the stream, edge will directly delivery
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stream to client. That is, when many clients connect to edge, there is only one
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connection to origin for each stream. This is the CDN(content delivery network).
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For example, the origin server is at beijing, there are 320 edge servers on other
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provience, each edge server serves 2000 clients. There are 640,000 users play this
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stream, and the bandwidth of CDN consumed 640Gbps; the origin server only serves 320
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connections from all edge servers.
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The edge server is design for huge cluster. Futhermore, the SRS edge can config with
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multiple origin servers, SRS will switch to next when current origin server crash, and
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the end user never disconnect when edge switch origin server.
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## Config
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Config the edge in vhost:
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```bash
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vhost __defaultVhost__ {
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# The config for cluster.
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cluster {
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# The cluster mode, local or remote.
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# local: It's an origin server, serve streams itself.
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# remote: It's an edge server, fetch or push stream to origin server.
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# default: local
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mode remote;
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# For edge(mode remote), user must specifies the origin server
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# format as: <server_name|ip>[:port]
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# @remark user can specifies multiple origin for error backup, by space,
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# for example, 192.168.1.100:1935 192.168.1.101:1935 192.168.1.102:1935
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origin 127.0.0.1:1935 localhost:1935;
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# For edge(mode remote), whether open the token traverse mode,
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# if token traverse on, all connections of edge will forward to origin to check(auth),
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# it's very important for the edge to do the token auth.
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# the better way is use http callback to do the token auth by the edge,
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# but if user prefer origin check(auth), the token_traverse if better solution.
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# default: off
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token_traverse off;
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# For edge(mode remote), the vhost to transform for edge,
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# to fetch from the specified vhost at origin,
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# if not specified, use the current vhost of edge in origin, the variable [vhost].
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# default: [vhost]
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vhost same.edge.srs.com;
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# For edge(mode remote), when upnode(forward to, edge push to, edge pull from) is srs,
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# it's strongly recommend to open the debug_srs_upnode,
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# when connect to upnode, it will take the debug info,
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# for example, the id, source id, pid.
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# please see https://ossrs.io/lts/en-us/docs/v4/doc/log
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# default: on
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debug_srs_upnode on;
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}
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}
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```
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The origin can specifies multiple servers.
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## Example
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The example below specifies how to config a origin and edge.
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The config of origin, see `origin.conf`：
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```bash
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listen 19350;
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pid objs/origin.pid;
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srs_log_file ./objs/origin.log;
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vhost __defaultVhost__ {
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}
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```
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The config of edge, see `edge.conf`：
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```bash
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listen 1935;
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pid objs/edge.pid;
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srs_log_file ./objs/edge.log;
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vhost __defaultVhost__ {
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cluster {
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mode remote;
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origin 127.0.0.1:19350;
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}
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}
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```
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## HLS Edge
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The edge is for RTMP, that is, when publish stream to origin, only origin server output
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the HLS, all edge server never output HLS util client access the RTMP stream on edge.
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That is, never config HLS on edge server, it's no use. The HLS delivery must use squid or
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traffic server to cache the HTTP origin server.
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## Transform Vhost
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The design of CDN stream system, always use `up.xxxx` and `down.xxxx` to operate them, for example, user publish to cdn by host `up.srs.com` and play by `down.srs.com`.
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SRS can config the edge mode to transform the host to origin, use the config `vhost down.srs.com` for up edge server.
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For more information, read the config of edge server.
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Winlin 2015.4
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