Add a k8s version of the docker-compose file

Note this version is very simplified compared to the docker-compose
and has some major limitations:
* It relies on hostPath and a nodeSelector to put all the components on a shared storage node
* It only supports use as a replication node (downloader, restreamer, backfiller, segment_coverage)
* It uses the k8s Ingress instead of the built-in nginx for http routing.
pull/173/head
Mike Lang 4 years ago
parent dea143cc0a
commit 28faff5c58

@ -0,0 +1,231 @@
// This is a jsonnet file, it generates kubernetes manifests.
// To generate and apply, run "jsonnet k8s.jsonnet | kubectl apply -f -"
// Note this file is only set up to generate manifests for a basic replication node,
// for the sake of simplicity.
{
config: {
// These are the important top-level settings.
// Change these to configure the services.
// Image tag (application version) to use.
// Note: "latest" is not recommended in production, as you can't be sure what version
// you're actually running, and must manually re-pull to get an updated copy.
image_tag: "latest",
// Twitch channels to capture.
// Channels suffixed with a '!' are considered "important" and will be retried more aggressively
// and warned about if they're not currently streaming.
channels: ["desertbus!", "db_chief", "db_high", "db_audio", "db_bus"],
// Stream qualities to capture
qualities: ["source", "480p"],
// The node selector and hostPath to use. All pods must be on the same host
// and use this hostpath in order to share the disk.
node_selector: {},
host_path: "/var/lib/wubloader",
// The local port within each container to bind the backdoor server on.
// You can exec into the container and telnet to this port to get a python shell.
backdoor_port: 1234,
// Other nodes to always backfill from. You should not include the local node.
// If you are using the database to find peers, you should leave this empty.
peers: [
],
// This node's name in the nodes table of the database
localhost: "node_name",
// The hostname to use in the Ingress
ingress_host: "wubloader.example.com",
// Connection args for the database.
// If database is defined in this config, host and port should be postgres:5432.
db_args: {
user: "vst",
password: "dbfh2019", // don't use default in production. Must not contain ' or \ as these are not escaped.
host: "postgres",
port: 5432,
dbname: "wubloader",
},
// The timestamp corresponding to 00:00 in bustime
bustime_start: "1970-01-01T00:00:00Z",
// Extra options to pass via environment variables,
// eg. log level, disabling stack sampling.
env: {
// Uncomment this to set log level to debug
// WUBLOADER_LOG_LEVEL: "DEBUG",
// Uncomment this to disable stacksampling performance monitoring
// WUBLOADER_DISABLE_STACKSAMPLER: "true",
},
},
// A few derived values.
// The connection string for the database. Constructed from db_args.
db_connect: std.join(" ", [
"%s='%s'" % [key, $.config.db_args[key]]
for key in std.objectFields($.config.db_args)
]),
// Cleaned up version of $.channels without importance markers
clean_channels: [std.split(c, '!')[0] for c in $.config.channels],
// k8s-formatted version of env dict
env_list: [
{name: key, value: $.config.env[key]}
for key in std.objectFields($.config.env)
],
// This function generates deployments for each service, since they only differ slightly,
// with only a different image, CLI args and possibly env vars.
// The image name is derived from the component name
// (eg. "downloader" is quay.io/ekimekim/wubloader-downloader)
// so we only pass in name, args and env vars (with the latter two optional).
// Optional kwargs work just like python.
deployment(name, args=[], env=[]):: {
kind: "Deployment",
apiVersion: "apps/v1",
metadata: {
name: "wubloader-%s" % name,
labels: {app: "wubloader", component: name},
},
spec: {
replicas: 1,
selector: {
matchLabels: {app: "wubloader", component: name},
},
template: {
metadata: {
labels: {app: "wubloader", component: name},
},
spec: {
containers: [
{
name: name,
image: "quay.io/ekimekim/wubloader-%s:%s" % [name, $.config.image_tag],
args: args,
volumeMounts: [{name: "data", mountPath: "/mnt"}],
env: $.env_list + env, // main env list combined with any deployment-specific ones
},
],
volumes: [
{
name: "data",
hostPath: {path: $.config.host_path},
},
],
nodeSelector: $.config.node_selector,
},
},
},
},
// This function generates a Service object for each service, since they're basically identical.
service(name): {
kind: "Service",
apiVersion: "v1",
metadata: {
name: "wubloader-%s" % name,
labels: {app: "wubloader", component: name},
},
spec: {
selector: {app: "wubloader", component: name},
ports: [{name: "http", port: 80, targetPort: 80}],
},
},
// The actual manifests.
// These are all deployments. Note that all components work fine if multiple are running
// (they may duplicate work, but not cause errors by stepping on each others' toes).
manifests: [
// The downloader watches the twitch stream and writes the HLS segments to disk
$.deployment("downloader", args=$.config.channels + [
"--base-dir", "/mnt",
"--qualities", std.join(",", $.config.qualities),
"--backdoor-port", std.toString($.config.backdoor_port),
"--metrics-port", "80",
]),
// The restreamer is a http server that fields requests for checking what segments exist
// and allows HLS streaming of segments from any requested timestamp
$.deployment("restreamer", args=[
"--base-dir", "/mnt",
"--backdoor-port", std.toString($.config.backdoor_port),
"--port", "80",
]),
// The backfiller periodically compares what segments exist locally to what exists on
// other nodes. If it finds ones it doesn't have, it downloads them.
// It can talk to the database to discover other wubloader nodes, or be given a static list.
$.deployment("backfiller", args=$.clean_channels + [
"--base-dir", "/mnt",
"--qualities", std.join(",", $.config.qualities),
"--static-nodes", std.join(",", $.config.peers),
"--backdoor-port", std.toString($.config.backdoor_port),
"--node-database", $.db_connect,
"--localhost", $.config.localhost,
"--metrics-port", "80",
]),
// Segment coverage is a monitoring helper that periodically scans available segments
// and reports stats. It also creates a "coverage map" image to represent this info.
// It puts this in the segment directory where nginx will serve it.
$.deployment("segment_coverage", args=$.clean_channels + [
"--base-dir", "/mnt",
"--qualities", std.join(",", $.config.qualities),
"--metrics-port", "80",
]),
// Normally nginx would be responsible for proxying requests to different services,
// but in k8s we can use Ingress to do that. However nginx is still needed to serve
// static content - segments as well as thrimbletrimmer.
$.deployment("nginx", env=[
{name: "THRIMBLETRIMMER", value: "true"},
{name: "SEGMENTS", value: "/mnt"},
]),
// Ingress to direct requests to the correct services.
{
kind: "Ingress",
apiVersion: "v1",
metadata: {
name: "wubloader",
labels: {app: "wubloader"},
},
spec: {
rules: [
{
host: $.config.ingress_host,
http: {
// Helper functions for defining the path rules below
local rule(name, path, type) = {
path: path,
pathType: type,
backend: {
serviceName: "wubloader-%s" % name,
servicePort: 80,
},
},
local metric_rule(name) = rule(name, "/metrics/%s" % name, "Exact"),
paths: [
// Map /metrics/NAME to each service (except restreamer)
metric_rule("downloader"),
metric_rule("backfiller"),
metric_rule("segment_coverage"),
// Map /segments and /thrimbletrimmer to the static content nginx
rule("nginx", "/segments", "Prefix"),
rule("nginx", "/thrimbletrimmer", "Prefix"),
// Map everything else to restreamer
rule("restreamer", "/", "Prefix"),
],
},
},
],
},
},
],
}.manifests // final output is just the manifest list, none of the other fields
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