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Datadog Agent Source Regression in v0.24x
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Problem
We noticed the following issue when upgrading from v0.23.3 to v0.24.0:
(1) CPU became spikey/less consistent
The charts below show how CPU explodes, Datadog forwarder error rates climb, HAProxy 5xx rates climb

(2) 504 error codes coming from the Datadog Agents writing to Vector for only the /api/beta/sketches endpoint
2022-11-15 22:52:12 UTC | CORE | ERROR | (pkg/forwarder/worker.go:184 in process) | Error while processing transaction: error "504 Gateway Time-out" while sending transaction to "http://vector-haproxy.vector.svc.cluster.local:6000/api/beta/sketches", rescheduling it: "<html><body><h1>504 Gateway Time-out</h1>\nThe server didn't respond in time.\n</body></html>\n"
This is also apparent in errors surfacing from HAProxy (deployed via the Vector Helm chart). HAProxy is using a leastconn balance strategy.
(3) Error logs coming from Vector for shutting down connections
{"host":"vector-599576bd9b-w2bq7","message":"error shutting down IO: Transport endpoint is not connected (os error 107)","metadata":{"kind":"event","level":"DEBUG","module_path":"hyper::proto::h1::conn","target":"hyper::proto::h1::conn"},"pid":1,"source_ty
pe":"internal_logs","timestamp":"2022-11-16T20:11:46.533762489Z"}
{"host":"vector-599576bd9b-w2bq7","message":"connection error: error shutting down connection: Transport endpoint is not connected (os error 107)","metadata":{"kind":"event","level":"DEBUG","module_path":"hyper::server::server::new_svc","target":"hyper::se
rver::server::new_svc"},"pid":1,"source_type":"internal_logs","timestamp":"2022-11-16T20:11:46.533777847Z"}
Configuration
data_dir: /vector-data-dir
api:
enabled: true
address: 127.0.0.1:8686
playground: false
sources:
internal_logs:
type: internal_logs
# Datadog Agent telemetry
datadog_agent:
type: datadog_agent
address: "0.0.0.0:6000"
multiple_outputs: true # To automatically separate metrics and logs
sinks:
console:
type: console
inputs:
- internal_logs
target: stdout
encoding:
codec: json
# Datadog metrics output
datadog_metrics:
type: datadog_metrics
inputs:
- <inputs>...
api_key: "${DATADOG_API_KEY}"
Version
0.24.0-distroless-libc
Debug Output
I can only recreate this issue in critical environments where I can't create this output information :(
Example Data
I'm not sure what the Datadog Agent is sending to this endpoint
Additional Context
We're running in AWS EKS 1.21 in
References
No response
We're looking into this, will keep you posted, @jonwinton !
Thanks @barieom! I wanted to add this screenshot of steady state CPU usage. Orange line is CPU requests, red line is CPU limit. Looking at network traffic there is are no outliers in terms of higher network load on a single pod.
Let me know if I can supply anything else to help!
Thanks for filing this issue @jonwinton.
It looks like the vector helm chart was used for configuration of vector.
Would you be able to provide the complete helm chart values used, and the chart version you are using?
This would expedite the investigation and reproduction effort.
Definitely @neuronull !
Chart Version: 0.14.0 One comment on this: we're blocked from upgrading due to our current EKS version not having the autoscaling APIs defined in current versions of the chart. We're in the progress of updating, but it'll be awhile
We use Argo for deployment of the chart but we have a fun Helm args combining pipeline, I need some time to get the full config together.
@neuronull here we go:
affinity:
podAntiAffinity:
preferredDuringSchedulingIgnoredDuringExecution:
- podAffinityTerm:
labelSelector:
matchExpressions:
- key: app.kubernetes.io/name
operator: In
values:
- vector
topologyKey: failure-domain.beta.kubernetes.io/zone
weight: 100
autoscaling:
enabled: true
targetCPUUtilizationPercentage: 80
targetMemoryUtilizationPercentage: 60
commonLabels:
tags.datadoghq.com/service: vector
tags.datadoghq.com/version: "0.24.0"
env:
- name: DATADOG_API_KEY
valueFrom:
secretKeyRef:
key: ...
name: ...
- name: DD_HOSTNAME
valueFrom:
fieldRef:
fieldPath: spec.nodeName
- name: VECTOR_POD_NAME
valueFrom:
fieldRef:
fieldPath: metadata.name
- name: VECTOR_VERSION
valueFrom:
fieldRef:
fieldPath: metadata.labels['tags.datadoghq.com/version']
extraVolumeMounts:
- mountPath: /mnt/secrets-store
name: vector-secrets
readOnly: true
extraVolumes:
- csi:
driver: secrets-store.csi.k8s.io
readOnly: true
volumeAttributes:
secretProviderClass: ...
name: vector-secrets
podDisruptionBudget:
enabled: true
minAvailable: 10%
podLabels:
tags.datadoghq.com/service: vector
podPriorityClassName: system-cluster-critical
role: Stateless-Aggregator
rollWorkload: true
serviceAccount:
annotations:
eks.amazonaws.com/role-arn: <role id>
create: true
updateStrategy:
rollingUpdate:
maxSurge: 0
maxUnavailable: 1
type: RollingUpdate
haproxy:
enabled: true
image:
tag: &version 2.6.6
resources:
requests:
cpu: 1000m
memory: 1Gi
limits:
cpu: 1000m
memory: 1Gi
autoscaling:
enabled: true
minReplicas: 9
maxReplicas: 50
podLabels:
tags.datadoghq.com/service: vector-haproxy
tags.datadoghq.com/version: *version
affinity:
podAntiAffinity:
preferredDuringSchedulingIgnoredDuringExecution:
- podAffinityTerm:
labelSelector:
matchExpressions:
- key: app.kubernetes.io/name
operator: In
values:
- vector
topologyKey: failure-domain.beta.kubernetes.io/zone
weight: 100
podAnnotations:
ad.datadoghq.com/haproxy.checks: |
{
"haproxy": {
"init_config": {},
"instances": [{
"use_openmetrics": true,
"openmetrics_endpoint": "http://%%host%%:1024/metrics",
"histogram_buckets_as_distributions": true,
"collect_counters_with_distributions": true
}]
}
}
customConfig: |
global
log stdout format raw local0
maxconn 4096
stats socket /tmp/haproxy
hard-stop-after {{ .Values.haproxy.terminationGracePeriodSeconds }}s
defaults
log global
option dontlognull
retries 10
option redispatch
option allbackups
timeout client 10s
timeout server 10s
timeout connect 5s
resolvers coredns
nameserver dns1 kube-dns.kube-system.svc.cluster.local:53
resolve_retries 3
timeout resolve 2s
timeout retry 1s
accepted_payload_size 8192
hold valid 10s
hold obsolete 60s
frontend stats
mode http
bind :::1024
option httplog
http-request use-service prometheus-exporter if { path /metrics }
stats enable
stats hide-version # Hide HAProxy version
stats realm Haproxy\ Statistics # Title text for popup window
stats uri /haproxy_stats # Stats URI
stats refresh 10s
frontend datadog-agent
mode http
bind :::6000
option httplog
option dontlog-normal
default_backend datadog-agent
backend datadog-agent
mode http
balance leastconn
option tcp-check
server-template srv 10 _datadog-agent._tcp.{{ include "vector.fullname" $ }}.{{ $.Release.Namespace }}.svc.cluster.local resolvers coredns check
Chart Version: 0.14.0 One comment on this: we're blocked from upgrading due to our current EKS version not having the autoscaling APIs defined in current versions of the chart. We're in the progress of updating, but it'll be awhile
Hey @jonwinton IIRC there's nothing really stopping us from backporting the HPA options to older API's. I think I stopped where I did because there was some amount of structural change that happened between API versions and I figured if someone needed the support we'd get an issue opened.
We'd be happy to get an issue opened for that support if that would help you upgrade.
@neuronull here we go:
Thanks @jonwinton !
Forgot to ask as well- what version of the Datadog Agent are you using? Was it also upgraded or did it's version stay the same? Can you share the DD Agent config as well?
Cheers~
Still investigating this but just had an observation.
In v0.24.0 #13406 contained a fix in the datadog_metrics sink. The sink was not properly utilizing the DD api key from the event metadata. Because your configuration is utilizing the datadog_agent source ,and the datadog_metrics sink and the datadog_agent source by default forwards the API key- v0.24.0 introduced a change in behavior for your config.
I'm wondering if the problem here is that the DD API key which is being sent to Vector from the Datadog Agent's configuration , is perhaps different than the one which is being configured in the helm chart via the secrets? (Or otherwise overriding)
By default, the datadog_agent source is configured to store the API key if it is found in the headers from the Datadog Agent requests.
To disable that, set store_api_key to false.
https://vector.dev/docs/reference/configuration/sources/datadog_agent/#store_api_key
Would you mind giving that a try @jonwinton ? Thanks!
Sorry for the delay @neuronull and @spencergilbert ! Had some holiday time off and everything. Let me get you that info.
@neuronull I did test setting store_api_key and it didn't help.
Forgot to ask as well- what version of the Datadog Agent are you using? Was it also upgraded or did it's version stay the same? Can you share the DD Agent config as well?
@neuronull the version of the DataDog agent has been locked to 7.39.1 for the duration of this test.
We'd be happy to get an issue opened for that support if that would help you upgrade.
@spencergilbert I think we're going to be stuck on the autoscaling/v1 API for the next 3-6 months, so if it's possible to support those versions that would be amazing 🙇
@jonwinton I see you mentioned you tried setting store_api_key. To clarify, did you try setting it to false? That is: store_api_key: false on the datadog_agent source. As @neuronull pointed out there was a fix in 0.24.0 to start using the API key that Agent sent metrics with when forwarding to Datadog, by default, to match the behavior of logs.
Also, is that the complete Helm configuration? I expected to see the Vector configuration in it, but I just see the HAProxy configuration.
@jszwedko yeah, tried setting it to false and it didn't change anything.
That is the full configuration other than the Vector configuration in the original issue body, which I'll re-paste below:
data_dir: /vector-data-dir
api:
enabled: true
address: 127.0.0.1:8686
playground: false
sources:
internal_logs:
type: internal_logs
# Datadog Agent telemetry
datadog_agent:
type: datadog_agent
address: "0.0.0.0:6000"
multiple_outputs: true # To automatically separate metrics and logs
store_api_key: false
sinks:
console:
type: console
inputs:
- internal_logs
target: stdout
encoding:
codec: json
# Datadog metrics output
datadog_metrics:
type: datadog_metrics
inputs:
- <inputs>...
api_key: "${DATADOG_API_KEY}"
In
v0.24.0#13406 contained a fix in thedatadog_metricssink.
Just correcting myself- That change I was pointing out was included in v0.23.0, so that whole line of inquiry which followed would be invalid.
Hi @jonwinton,
I've been trying to reproduce this locally and am not having much luck so far. :disappointed: Will summarize what I've tried and some observations, and maybe something will jump out at you.
Additional questions for you:
- Do you have any additional log snippets you could provide? For example, is Vector logging any Errors (not debug logs). And, perhaps the error logs from HAProxy?
- Since we're having trouble reproducing it, would you be open to trying some nightly builds between v0.23.3 and 0.24.0, and observing the first build which exhibits the issue? This could give us hints to which commits might have caused the issue and additionally raise confidence in the issue.
- Have you attempted this upgrade from 0.23.3 to 0.24.0 multiple times or just once?
- Have you performed similar upgrades of Vector in this environment before?
General observations:
-
The message "error shutting down IO" from the Vector logs, seems to be either (likely I suspect) benign or it's not a new issue with 0.24.0, or not specifically tied to the 504 error observed in the Agent logs.
- This is a debug level print coming from the
hypercrate - I saw this message in every iteration I tried, regardless of whether I upgraded/restarted the Vector pod.
- This is a debug level print coming from the
-
So far I haven't been able to get a 504 error to show in the Agent logs
- I've seen a 503 error a couple of times, between when Vector pod was uninstalled, and when it was re-installed, but it occurred only once in each case and went away after Vector was running again, and didn't show up every time. 503 while Vector is down seems pretty expected.
My setup:
- minikube
- Agent using the helm values outlined below.
- Vector using the helm values outlined below.
- A dogstasd client using the program outlined below.
Permutations I've tried:
- vector 0.23.3 -> vector 0.24.0
- vector 0.23.3 restart vector
- vector 0.24.4 restart vector
- all of the above with and without restarting the Agent pod
- variations on the dogstastd client to adjust the emission rate of distribution metrics and number of distribution metrics.
- variations on the delay between uninstalling vector and re-installing vector
dogstastd program
from datadog import initialize, statsd
import time
import random
import sys
def log(msg):
sys.stdout.write('{}: {}\n'.format(time.strftime("%H:%M:%S"), msg))
sys.stdout.flush()
options = {
'statsd_host':'172.17.0.3',
'statsd_port':8125
}
log("initializing")
initialize(**options)
log("initialized")
while (1):
log("distribution")
for n in range(0,99):
name = "foo_metric.distribution_" + str(n)
value = random.randint(0,999)
statsd.distribution(name, value, tags=["environment:baz"])
time.sleep(1)
Agent helm values
datadog:
apiKey: <redacted>
containerExclude: "name:vector"
logs:
enabled: true
containerCollectAll: true
apm:
enabled: false
clusterAgent:
enabled: false
agents:
useConfigMap: true
image:
tag: 7.39.1
customAgentConfig:
kubelet_tls_verify: false
vector:
logs:
enabled: true
url: "http://vector-haproxy.default:8282"
metrics:
enabled: true
url: "http://vector-haproxy.default:8282"
dogstatsd_non_local_traffic: true
ports:
- containerPort: 8125
hostPort: 8125
name: dogstatsdport
protocol: UDP
Vector helm values
Effectively the same as your provided values , with the exception of tagging specific images, and hard coding the DD API key.
Hey! Thanks for all the details! I'll try and answer everything here and will come back with deeper answers for some things I need to retrieve/update log levels for.
Do you have any additional log snippets you could provide? For example, is Vector logging any Errors (not debug logs). And, perhaps the error logs from HAProxy?
Let me go get some of those a little later. Pre-planned DR game day going on so a little distracted 😬
Since we're having trouble reproducing it, would you be open to trying some nightly builds between v0.23.3 and 0.24.0, and observing the first build which exhibits the issue? This could give us hints to which commits might have caused the issue and additionally raise confidence in the issue.
🤦 I'm sad I didn't think about doing this already. I will definitely do this.
Have you attempted this upgrade from 0.23.3 to 0.24.0 multiple times or just once?
Multiple times!
Have you performed similar upgrades of Vector in this environment before?
Yeah, we jumped onto vector in the 0.1x versions and slowly bumped up each version until 0.24.0
One other piece of context that might be helpful: this issue first appeared in our largest staging environment, so I'm wondering if it's related to volume. Are y'all running load testing benchmarks in CI? Screenshot to show the load where we're first encountering the error.

I will definitely do this.
Thanks a bunch!
One other piece of context that might be helpful: this issue first appeared in our largest staging environment, so I'm wondering if it's related to volume. Are y'all running load testing benchmarks in CI? Screenshot to show the load where we're first encountering the error.
We do some sense of load testing within our soak regression tests- generally those soak tests will try to hit vector with the allocated resources available. But we don't have explicit testing to evaluate usage under different loads.
It is good to know that it might be volume related- I can take that into consideration for repro efforts going forward.
So sorry for the delay @neuronull, but I'm working through the nightlies now. Will get you a report this week so it's ready for the new year 🙇
@neuronull ok here are the results:
- I found that the regression occurs with the
nightly-2022-08-17-distroless-libctag - The changes for that build can be found here
- I know we've documented it before, but it's the same behavior as before once that nightly tag lands

Thanks for bisecting that down @jonwinton ! Just to confirm, do I take the above to mean that nightly-2022-08-16-distroless-libc did not exhibit the issue?
@jszwedko correct! Here's a screenshot showing the version was nightly-2022-08-16-distroless-libc right before deploying the 2022-08-17 tag and everything was working as expected.
I'm working with DataDog Support to give you access to a notebook with the entire breakdown, but screenshots for now.
Thanks @jonwinton ! That would seem to narrow down the suspicious commits to https://github.com/vectordotdev/vector/compare/ba1e1c4...01c7a36 then. Nothing immediately jumps out, but it should give us a much better place to start investigating from. The person investigating this is OOO this week, but we'll pick it back up in the new year. Appreciate all of the added context!
Sounds good! Yeah I was beginning to look at https://github.com/vectordotdev/vector/pull/13973 since we only see the errors come up for distribution data, but I need a Rust pro to help out. That said, if any tagged releases can be pushed out that have any changes to test in our env, I can easily deploy them.
See y'all next year!
Thanks for going through that effort and providing all that data @jonwinton , really helps!
I believe the hdrhistogram crate updated in #13973 can be ruled out as it only seems to be used in some example code.
After looking at that commit range, the one that stands out most suspiciously is #13960.
At first glance it looks like its unrelated because the code is only operating over Counter metric types, and here the affect type is distribution.
But then I noticed this in the helm values ...
"collect_counters_with_distributions": true
I'm currently working on finding out what that actually translates to in terms of the Agent's behavior.
But so far that commit is really the only one that jumps out to me.
We could also try a test of a private build containing the commits from 8-17 but minus this one.
@neuronull dang, nice digging! 🙇
A private image works, or if you can give me the build commands for generating the libc image I can push an image into our private ECR repo. I tried digging into the build pipeline a bit, but my lack of Rust familiarity is holding me back a bit.
Thanks @jonwinton !
Here are the commands to get to the correct state of the repo:
- git checkout 01c7a36
- git revert ef22eb9
2.a To resolve the conflict, open lib/vector-core/Cargo.toml and you want the line 89 to be
test = ["vector-common/test"]
To build the docker image to your local cache:
- make package-deb-x86_64-unknown-musl 1.a (you can select different architectures too, see the available ones in Makefile)
- PUSH=false ./scripts/build-docker.sh
Let us know how that goes or if you have any problems! Very curious to hear the result.
@jonwinton , sorry for the spam- Ignore that last comment's instructions (there are some incorrect bits). We're working on improving the procedure to follow. In the meantime, I'll create the image and push it to the vector repo for you.
Alright, this image should do the trick @jonwinton. It contains that nightly build minus ef22eb9.
timberio/vector:39c98e3-distroless-libc
Perfect! I'll test this now
@neuronull confirmed that we don't see the same issue with this version! Thank you for pushing that version out 🙇
I guess next steps would be entirely on y'all's end?
Oh dang, looking at that PR more, we're interested in maintaining the fix for this bug: https://github.com/vectordotdev/vector/issues/13870
We're also dealing with interval issues and this would be helpful once we can safely upgrade 😬