vector: input net bandwidth > output net bandwidth causes vector OOM

Vector Version

vector 0.15.0 (x86_64-unknown-linux-gnu b2992c9 2021-06-30)
(Nightly)

Vector Configuration File

data_dir = "/var/vector/data"


[sources.fluent_source]
  type = "fluent"
  address = "0.0.0.0:24224"


[sinks.elasticsearch-fluent]
  # General
  type = "elasticsearch" 
  inputs = ["fluent_source"] 
  compression = "none" # optional,
  endpoint = "http://10.1.0.9:9200/" 
  index = "{{ viaq_index_name }}-%Y-%m-%d"
  healthcheck.enabled = true 

Debug Output

https://gist.github.com/AntonSmolkov/10a10cb1749d16418f71419f31cc6209

Expected Behavior

Fluent source does not cause OOM

Actual Behavior

Fluent source causes OOM. Vector eats all machines memory (8GiB in my case)

[Mon Jul 12 13:10:23 2021] oom-kill:constraint=CONSTRAINT_NONE,nodemask=(null),cpuset=/,mems_allowed=0,global_oom,task_memcg=/system.slice/vector.service,task=vector,pid=1082674,uid=1001
[Mon Jul 12 13:10:23 2021] Out of memory: Killed process 1082674 (vector) total-vm:7494848kB, anon-rss:6939664kB, file-rss:0kB, shmem-rss:0kB, UID:1001 pgtables:14032kB oom_score_adj:0
[Mon Jul 12 13:10:23 2021] oom_reaper: reaped process 1082674 (vector), now anon-rss:0kB, file-rss:0kB, shmem-rss:0kB

Example Data

Additional Context

~200 logs/per sec from OpenShift.

Vector is located on Azure - Standard_D2_v3 instance with 1GiB/sec outbound traffic limit. Inbound traffic is unlimited and effectevely is 40GiB/sec(link speed)

Fluentd under the same circumstances works fine and consumes only 1.5 GiB of RAM.

References