Is your feature request related to a problem? Please describe.
When on non-EC2 environments, it's possible to use the env var AWS_EC2_METADATA_SERVICE_ENDPOINT to use IMDS on a host other than 169.254.169.254. The aws sdk docs describe the env var more. On a related note you may also want to support the IPv6 endpoint of [fd00:ec2::254] as another default.
Describe the solution you'd like
If the env var is set, its value is respected and used instead of 169.254.169.254.
Describe alternatives you've considered
Doing some shenanigans with iptables or other routing tools.
Additional context
I'm trying to authenticate to AWS on a non-EC2 host with IMDS.
The cli can authenticate fine for example:
$ aws sts get-caller-identity --no-cli-pager
{
"UserId": "A********P:40907cc9d91df2bfaa7c523ca4feee87",
"Account": "************",
"Arn": "arn:aws:sts::*********:assumed-role/********/40907cc9d91df2bfaa7c523ca4feee87"
}While fluent-bit is confused:
$ /opt/fluent-bit/bin/fluent-bit
Fluent Bit v4.0.9
* Copyright (C) 2015-2025 The Fluent Bit Authors
* Fluent Bit is a CNCF sub-project under the umbrella of Fluentd
* https://fluentbit.io
______ _ _ ______ _ _ ___ _____
| ___| | | | | ___ (_) | / || _ |
| |_ | |_ _ ___ _ __ | |_ | |_/ /_| |_ __ __/ /| || |/' |
| _| | | | | |/ _ \ '_ \| __| | ___ \ | __| \ \ / / /_| || /| |
| | | | |_| | __/ | | | |_ | |_/ / | |_ \ V /\___ |\ |_/ /
\_| |_|\__,_|\___|_| |_|\__| \____/|_|\__| \_/ |_(_)___/
[2025/09/10 21:44:00] [ info] [fluent bit] version=4.0.9, commit=, pid=83097
[2025/09/10 21:44:00] [ info] [storage] ver=1.5.3, type=memory, sync=normal, checksum=off, max_chunks_up=128
[2025/09/10 21:44:00] [ info] [simd ] SSE2
[2025/09/10 21:44:00] [ info] [cmetrics] version=1.0.5
[2025/09/10 21:44:00] [ info] [ctraces ] version=0.6.6
[2025/09/10 21:44:00] [ info] [input:tail:tail.0] initializing
[2025/09/10 21:44:00] [ info] [input:tail:tail.0] storage_strategy='memory' (memory only)
[2025/09/10 21:44:01] [error] [net] connection #104 timeout after 1 seconds to: 169.254.169.254:80
[2025/09/10 21:44:01] [ warn] [imds] unable to evaluate IMDS version
[2025/09/10 21:44:01] [ info] [sp] stream processor started
Is your feature request related to a problem? Please describe.
When on non-EC2 environments, it's possible to use the env var
AWS_EC2_METADATA_SERVICE_ENDPOINTto use IMDS on a host other than169.254.169.254. The aws sdk docs describe the env var more. On a related note you may also want to support the IPv6 endpoint of[fd00:ec2::254]as another default.Describe the solution you'd like
If the env var is set, its value is respected and used instead of
169.254.169.254.Describe alternatives you've considered
Doing some shenanigans with
iptablesor other routing tools.Additional context
I'm trying to authenticate to AWS on a non-EC2 host with IMDS.
The cli can authenticate fine for example:
$ aws sts get-caller-identity --no-cli-pager { "UserId": "A********P:40907cc9d91df2bfaa7c523ca4feee87", "Account": "************", "Arn": "arn:aws:sts::*********:assumed-role/********/40907cc9d91df2bfaa7c523ca4feee87" }While
fluent-bitis confused: