What always puzzles me about OpenTelemetry is that tracing, metrics and logs are all designed independently. I wish there was a way I could just annotate my code base once, and let the ultimate decision to expose something as a metric/log/trace be dynamic at runtime.
For example, if I look at a graph in monitoring dashboard and see something suspicious, I’d like to say: “The next time something like this occurs again, please save me a trace.” I should be able to just do that with a single mouse click.
I remember them releasing the tracing spec/SDKs and saying “now let’s move on to metrics/logs.” That never sat right with me.
If I understand that correctly, it means your app always creates traces, and Grafana Cloud is responsible for sampling/aggregating. That may be prohibitively expensive in terms of CPU/network load.
What I’m suggesting is that your apps by default only send metrics to your monitoring system, but that the monitoring system can specifically ask to “upgrade” metrics to traces. Or to log entries.
The same thing with metric cardinality: by default, only report metrics in a fully aggregated manner. But do tell the monitoring system how they can potentially be broken up if needed (i.e., which labels to add).
> The same thing with metric cardinality: by default, only report metrics in a fully aggregated manner. But do tell the monitoring system how they can potentially be broken up if needed (i.e., which labels to add).
How does the monitoring system have any of the context to add labels? That would only exist in application memory.
> That may be prohibitively expensive in terms of CPU/network load.
In practice I've not experienced this even on quite high request rates. While it isn't free, exporting everything has been cheap enough that the real cost in dollars spent is basically marginal (it's _storing_ the data that's expensive)
> How does the monitoring system have any of the context to add labels? That would only exist in application memory.
Indeed. If you have a protocol that doesn’t allow exposing that kind of information, then that only lives in application memory. But my suggestion is that it’s exposed.
OTel is so frustrating. If it wasn't shaping to be the clear winner in the space, I wouldn't complain about it as much. But today:
1. Every major vendor is still in some weird alpha/beta support for OTel even after all this time.
2. The performance hit is substantial and makes you question what the point of performance instrumentation is if you need twice as much compute/RAM to run the same workload now.
3. Serverless runtimes pay a heavy penalty for cold starts with OTel.
4. You're basically forced to run both gateway collectors and edge collectors for any realistic usage.
5. You still need to configure destination exporters in unique ways. This leaves you questioning what the value of OTel was.
6. Vendors that go beyond the scope of what OTel covers still need their own bespoke instrumentation. What was the point of any of this then?
I disagree. I'm an observability geek, and OTel is... fine.
It's missing a few things that I'd like, but I was able to implement them myself. I guess the major design issue is that the sampling decision is made at the _start_ of the segment. So I hacked up a few improvements:
1. Ability to mark segments as "boring", so they are dropped before the export. For things like healthchecks, empty "get the pending jobs" queries, etc.
2. Ability to downgrade errors for segments that are expected to return an error (e.g. HEAD on a non-existing object in S3 to check if there's a cached blob).
It is crazy to me how often people don't grok how to design software well.
1. The worst thing you can do is try to stuff too many things into one specification. So you want an API? That's great. What's that? You want a rigid set of types so that any tiny changes over time aren't compatible? You want to try to define every conceivable use case as a new call? You want to combine multiple elements from different domains into one flat set of functions? You don't have any hierarchy or inheritance? You don't support extensions?
2. The second-worst thing you can do is to force a whole lot of different people to go through a single standards body. So you want to support a thousand different 3rd party components. What's that? You want to require everyone get their adapter approved by one group? And there's only one supported adapter per 3rd party component?
If you're trying to feed an entire city, it's logistically incredibly difficult to try to do it all yourself. If instead you just define where food can be dropped off or picked up, and ask volunteers to bring their own food there whenever they can/want, now you don't have a logistical nightmare on your hands anymore. The tech alternative? Add support for "plugins", make the plugin interface incredibly loose/backwards-compatible/layered, and invite people to publish their own plugins. If you under-engineer it, it actually works better.
The alternative is vendor lockin, $$$, and spotty support for complex environments with zero chance of ever getting 100% coverage.
At least with Open Telemetry, anyone can write an OTLP "source" using free, open specifications, and it'll "just work" with dozens of third-party "sinks". That's huge!
Sure, there's a lot of experimental tags on semantic conventions, but at the end of the day, that's not that critical. It's just data: most sinks don't "interpret" these tags, they just display them as-is, so changes aren't breaking changes.
The alternative is Prometheus (which is freaking great) and Jaegar (which is freaking great), each alone. This is better, because Otel is trying to put two distinct things (monitoring and metrics, distributed tracing) into one package, because they know how to use neither.
Neither Prometheus metrics nor Jaeger traces are magic bullets. Neither of them are complicated, either, and in fact the fact that they're not complicated is their greatest strength. You can and should understand every facet of what they entail. You should build the (very small) shims that they need for your company's framework every time. It's not hard. It's not hard because it's not complicated. The fact that it's not complicated seems to break people's brains. They are accurate because they're simple and they're easy to work with because they're simple, and OTel is neither.
Prometheus is so easy to add and if you need more scale, there is mimir and a few other options with similar client semantics. I really can't imagine reaching for a framework APK that tries to anticipate every possible thing I would want telemtered, and is inevitably missing all the domain specific derived channels I need. Even prepackaged Prometheus exporters are usually overkill.
What always puzzles me about OpenTelemetry is that tracing, metrics and logs are all designed independently. I wish there was a way I could just annotate my code base once, and let the ultimate decision to expose something as a metric/log/trace be dynamic at runtime.
For example, if I look at a graph in monitoring dashboard and see something suspicious, I’d like to say: “The next time something like this occurs again, please save me a trace.” I should be able to just do that with a single mouse click.
I remember them releasing the tracing spec/SDKs and saying “now let’s move on to metrics/logs.” That never sat right with me.
One strategy do to do that is to trace everything by default and select what to sample later, e.g. https://grafana.com/docs/grafana-cloud/observe-and-act/adapt...
If I understand that correctly, it means your app always creates traces, and Grafana Cloud is responsible for sampling/aggregating. That may be prohibitively expensive in terms of CPU/network load.
What I’m suggesting is that your apps by default only send metrics to your monitoring system, but that the monitoring system can specifically ask to “upgrade” metrics to traces. Or to log entries.
The same thing with metric cardinality: by default, only report metrics in a fully aggregated manner. But do tell the monitoring system how they can potentially be broken up if needed (i.e., which labels to add).
> The same thing with metric cardinality: by default, only report metrics in a fully aggregated manner. But do tell the monitoring system how they can potentially be broken up if needed (i.e., which labels to add).
How does the monitoring system have any of the context to add labels? That would only exist in application memory.
Grafana went the other way - your app exports all labels, and then you selectively aggregate on ingest: https://grafana.com/docs/grafana-cloud/observe-and-act/adapt...
> That may be prohibitively expensive in terms of CPU/network load.
In practice I've not experienced this even on quite high request rates. While it isn't free, exporting everything has been cheap enough that the real cost in dollars spent is basically marginal (it's _storing_ the data that's expensive)
> How does the monitoring system have any of the context to add labels? That would only exist in application memory.
Indeed. If you have a protocol that doesn’t allow exposing that kind of information, then that only lives in application memory. But my suggestion is that it’s exposed.
OTel is so frustrating. If it wasn't shaping to be the clear winner in the space, I wouldn't complain about it as much. But today:
1. Every major vendor is still in some weird alpha/beta support for OTel even after all this time.
2. The performance hit is substantial and makes you question what the point of performance instrumentation is if you need twice as much compute/RAM to run the same workload now.
3. Serverless runtimes pay a heavy penalty for cold starts with OTel.
4. You're basically forced to run both gateway collectors and edge collectors for any realistic usage.
5. You still need to configure destination exporters in unique ways. This leaves you questioning what the value of OTel was.
6. Vendors that go beyond the scope of what OTel covers still need their own bespoke instrumentation. What was the point of any of this then?
I disagree. I'm an observability geek, and OTel is... fine.
It's missing a few things that I'd like, but I was able to implement them myself. I guess the major design issue is that the sampling decision is made at the _start_ of the segment. So I hacked up a few improvements:
1. Ability to mark segments as "boring", so they are dropped before the export. For things like healthchecks, empty "get the pending jobs" queries, etc.
2. Ability to downgrade errors for segments that are expected to return an error (e.g. HEAD on a non-existing object in S3 to check if there's a cached blob).
I've never found instrumentation to be a huge issue. Sure it takes more effort but you get a lot more value once you understand _business_ events.
I wish otel was never there. It is badly designed abstraction and due to otel the code gets very very messy and bad.
It is crazy to me how often people don't grok how to design software well.
1. The worst thing you can do is try to stuff too many things into one specification. So you want an API? That's great. What's that? You want a rigid set of types so that any tiny changes over time aren't compatible? You want to try to define every conceivable use case as a new call? You want to combine multiple elements from different domains into one flat set of functions? You don't have any hierarchy or inheritance? You don't support extensions?
2. The second-worst thing you can do is to force a whole lot of different people to go through a single standards body. So you want to support a thousand different 3rd party components. What's that? You want to require everyone get their adapter approved by one group? And there's only one supported adapter per 3rd party component?
If you're trying to feed an entire city, it's logistically incredibly difficult to try to do it all yourself. If instead you just define where food can be dropped off or picked up, and ask volunteers to bring their own food there whenever they can/want, now you don't have a logistical nightmare on your hands anymore. The tech alternative? Add support for "plugins", make the plugin interface incredibly loose/backwards-compatible/layered, and invite people to publish their own plugins. If you under-engineer it, it actually works better.
The alternative is vendor lockin, $$$, and spotty support for complex environments with zero chance of ever getting 100% coverage.
At least with Open Telemetry, anyone can write an OTLP "source" using free, open specifications, and it'll "just work" with dozens of third-party "sinks". That's huge!
Sure, there's a lot of experimental tags on semantic conventions, but at the end of the day, that's not that critical. It's just data: most sinks don't "interpret" these tags, they just display them as-is, so changes aren't breaking changes.
The alternative is Prometheus (which is freaking great) and Jaegar (which is freaking great), each alone. This is better, because Otel is trying to put two distinct things (monitoring and metrics, distributed tracing) into one package, because they know how to use neither.
Neither Prometheus metrics nor Jaeger traces are magic bullets. Neither of them are complicated, either, and in fact the fact that they're not complicated is their greatest strength. You can and should understand every facet of what they entail. You should build the (very small) shims that they need for your company's framework every time. It's not hard. It's not hard because it's not complicated. The fact that it's not complicated seems to break people's brains. They are accurate because they're simple and they're easy to work with because they're simple, and OTel is neither.
Prometheus is so easy to add and if you need more scale, there is mimir and a few other options with similar client semantics. I really can't imagine reaching for a framework APK that tries to anticipate every possible thing I would want telemtered, and is inevitably missing all the domain specific derived channels I need. Even prepackaged Prometheus exporters are usually overkill.
I’ve built custom Prometheus metrics very easily and had node exporter pick up the .prom files. Python and bash scripts reading and translating.
Node exporter runs on my Prometheus server next to Blackbox Exporter. Blackbox Exporter handles TLS expiry metrics.
OTEL metrics are a bit awkward, but they work just fine with Prometheus.
Jaeger uses the OTLP protocol nowadays. So it _is_ OTEL.
(TFA author is not me.)