b3lb

B3LB

BigBlueButton is an open source web conferencing system for online learning.

B3LB is an open source metrics based load balancer that manages a pool of BigBlueButton servers. It works like a proxy and makes the pool of servers appears like a single server. Send standard BigBlueButton API requests and B3LB distributes those request to the least loaded BigBlueButton server in the pool.

Architecture

A deployment of B3LB requires serveral components to get running:

• At least 2 BigBlueButton servers containing a telegraf server agent
• B3LB loadbalancer server
• Redis database
• InfluxDB database

Currently, to compute the least loaded BigBlueButton server, B3LB computes the mean or average of the cpu and memory sum metric records for the last 5 minutes and take the lowest average. Check balancer code for more details.

Installation

BigBlueButton

Check official BigBlueButton installation documentation.

InfluxDB

Check official InfluxDB v2 installation documentation. Once your InfluxDB runs, create an InfluxDB api token using the UI or the following instructions:

export INFLUXDB_ORG=b3lb # B3LB InfluxDB organization
export INFLUXDB_BUCKET=bucket # B3LB InfluxDB bucket
export INFLUXDB_TOKEN=Zq9wLsmhnW5UtOiPJApUv1cTVJfwXsTgl_pCkiTikQ3g2YGPtS5HqsXef-Wf5pUU3wjY3nVWTYRI-Wc8LjbDfg== # InfluxDB API token.
influx setup --name b3lb --org $INFLUXDB_ORG --username admin --password password --token $INFLUX_TOKEN --bucket $INFLUXDB_BUCKET --retention 0 --force

Telegraf

Install Telegraf on your BigBlueButton servers. Check official Telegraf installation documentation. The following is the minimal configuraton. Add it into telegraf.conf file:

[global_tags]
  b3lb_host="${B3LB_HOST}"

# Configuration for telegraf agent
[agent]
  ## Default data collection interval for all inputs
  interval = "10s"
  ## Rounds collection interval to 'interval'
  ## ie, if interval="10s" then always collect on :00, :10, :20, etc.
  round_interval = true

  ## Telegraf will send metrics to outputs in batches of at most
  ## metric_batch_size metrics.
  ## This controls the size of writes that Telegraf sends to output plugins.
  metric_batch_size = 1000

  ## For failed writes, telegraf will cache metric_buffer_limit metrics for each
  ## output, and will flush this buffer on a successful write. Oldest metrics
  ## are dropped first when this buffer fills.
  ## This buffer only fills when writes fail to output plugin(s).
  metric_buffer_limit = 10000

  ## Collection jitter is used to jitter the collection by a random amount.
  ## Each plugin will sleep for a random time within jitter before collecting.
  ## This can be used to avoid many plugins querying things like sysfs at the
  ## same time, which can have a measurable effect on the system.
  collection_jitter = "0s"

  ## Default flushing interval for all outputs. Maximum flush_interval will be
  ## flush_interval + flush_jitter
  flush_interval = "10s"
  ## Jitter the flush interval by a random amount. This is primarily to avoid
  ## large write spikes for users running a large number of telegraf instances.
  ## ie, a jitter of 5s and interval 10s means flushes will happen every 10-15s
  flush_jitter = "0s"

  ## By default or when set to "0s", precision will be set to the same
  ## timestamp order as the collection interval, with the maximum being 1s.
  ##   ie, when interval = "10s", precision will be "1s"
  ##       when interval = "250ms", precision will be "1ms"
  ## Precision will NOT be used for service inputs. It is up to each individual
  ## service input to set the timestamp at the appropriate precision.
  ## Valid time units are "ns", "us" (or "µs"), "ms", "s".
  precision = ""

  ## Logging configuration:
  ## Run telegraf with debug log messages.
  debug = false
  ## Run telegraf in quiet mode (error log messages only).
  quiet = false
  ## Specify the log file name. The empty string means to log to stderr.
  logfile = ""

  ## Override default hostname, if empty use os.Hostname()
  hostname = ""
  ## If set to true, do no set the "host" tag in the telegraf agent.
  omit_hostname = false
[[outputs.influxdb_v2]]
  urls = ["${INFLUXDB_URL}"]

  ## Token for authentication.
  token = "${INFLUXDB_TOKEN}"

  ## Organization is the name of the organization you wish to write to; must exist.
  organization = "${INFLUXDB_ORG}"

  ## Destination bucket to write into.
  bucket = "${INFLUXDB_BUCKET}"
[[inputs.cpu]]
  ## Whether to report per-cpu stats or not
  percpu = true
  ## Whether to report total system cpu stats or not
  totalcpu = true
  ## If true, collect raw CPU time metrics.
  collect_cpu_time = false
  ## If true, compute and report the sum of all non-idle CPU states.
  report_active = false
[[inputs.mem]]
[[inputs.net]]

Edit /etc/default/telegraf file and add the following variables:

B3LB_HOST= # Your public bigbluebutton url like https://yourbbbhost/bigbluebutton
INFLUXDB_URL= # InfluxDB url
INFLUXDB_TOKEN=Zq9wLsmhnW5UtOiPJApUv1cTVJfwXsTgl_pCkiTikQ3g2YGPtS5HqsXef-Wf5pUU3wjY3nVWTYRI-Wc8LjbDfg== # Generated InfluxDB api token
INFLUXDB_ORG=b3lb # InfluxDB organization
INFLUXDB_BUCKET=bucket # InfluxDB bucket

Restart your telegraf server agent:

systemctl restart telegraf

Redis

Check official Redis installaton guide. Configure Redis using persistance mode.

B3LB load balancer

Download the latest release. Add a configuration file:

---
bigbluebutton:
  secret: 0ol5t44UR21rrP0xL5ou7IBFumWF3GENebgW1RyTfbU # Your B3LB secret. It works like a BigBlueButton secret.
admin:
  api_key: kgpqrTipM2yjcXwz5pOxBKViE9oNX76R # Admin API key. Used to call admin rest endpoints
balancer:
  metrics_range: -5m # metrics range used by balancer to compute the next bigbluebutton instance
  cpu_limit: 100 # max cpu % average in range (metrics_range configuration). If the metric is higher than the configuration, the bigbluebutton instance could not be balanced
  mem_limit: 100 # max memory % average in range (metrics_range configuration). If the metric is higher than the configuration, the bigbluebutton instance could not be balanced
port: 8090 # B3LB port
redis: # Redis configuration
  address:
  password:
  database: 0
influxdb: # InfluxDB Configuration
  address:
  token: 
  organization:
  bucket:
...

Launch B3LB with -config flag pointing previous config file.

Manage B3LB

Use the admin API to list, add and delete BigBlueButton instance inside B3LB load balancer.

List BigBlueButton instances

curl -s -G -X GET http://localhost:8090/admin/servers -H "Authorization: $API_KEY" | jq "."

Add a BigBlueButton instance

curl -s -X POST http://localhost:8090/admin/servers -H "Authorization: $API_KEY" -H 'Content-Type: application/json' -d "{\"url\":\"$INSTANCE_URL\", \"secret\": \"$INSTANCE_SECRET\"}" | jq "."

Delete a BigBlueButton instance

curl -G -X DELETE http://localhost:8090/admin/servers -H "Authorization: $API_KEY" --data-urlencode "url=$INSTANCE_URL" | jq "."

Roadmap/

Checkout B3LB public roadmap.