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Similar experience here. We put a lot of time and effort into making our monitoring system more highly available than the thing it is monitoring. Not only that,

Similar experience here. We put a lot of time and effort into making our monitoring system more highly available than the thing it is monitoring. Not only that, only scaling vertically on a single node doesn't seem like a good design. When you're spread across many cloud providers, some on premise and a bunch of acquisition legacy stuff the polling and firewall opening becomes a blocker. There are ways to poll things and push metrics without opening millions of firewall ports to every security group. Sensu does that quite well, and it scales. I'm not pitching that as the saviour either as that has other trade-offs. However, Prometheus as far as I can see will suffer from the 2 points you make and all of the workarounds in terms of running duplicate identical nodes and federating them also come with various drawbacks. There are quite a few cloud providers who do an awesome job at providing those requirements. I think the only blocker on those is the current pricing model. As soon as somebody does something disruptive in this area I can see a great deal of convergence to it.

bbrazil 10y ago
> Not only that, only scaling vertically on a single node doesn't seem like a good design. For Prometheus at least, we're so efficient that it actually works out okay for the vast majority of users. You'd typically need thousands of instances doing the same thing inside a single datacenter before you get into our (admittedly more involved) horizontal sharding approach. http://www.robustperception.io/scaling-and-federating-prometheus/ http://www.robustperception.io/scaling-and-federating-promet... has more information. > There are ways to poll things and push metrics without opening millions of firewall ports to every security group. Sensu does that quite well, and it scales. I don't think that's quite a fair comparison. Sensu Just Works when there's no outbound firewall, Prometheus Just Works when there's no inbound firewall. If you add the other direction of firewall for either then things break down.
- Millenis 10y ago
  Hi, honestly this feels like the conversation our team had a few years ago about Nagios. Some people were happy with pockets of monitoring servers dotted around with wiki pages full of links to get to them. It took a long time to clean that up and finally end up with a single central service. The outbound vs inbound firewalls is totally a fair comparison. At almost every company I have worked for the perimeter security blocks all incoming ports. Most places have no outbound port restrictions, or when they do they usually always have a proxy for traffic to go out (like https for updates etc). This is what makes the design of outbound only connections considerably better (Sensu, Datadog, insert pretty much any SaaS vendor). I honestly don't know of any company who would open up such an extreme number of ports required to allow scraping from an external monitoring tool. In a large enterprise you want to host the monitoring tool as a service for other groups which means potentially in a totally different data center or cloud and allowing a small list of subnets 'in' is considerably better than exposing every single server to external access. For the scaling I'm not sure I totally agree. There is a reason why distributed systems exist and that is to scale efficiently with some degree of redundancy baked in. Single node HA is probably the most inefficient method of scaling. It sounds like Prometheus needs to run properly on a single box for simplicity but over time needs to be broken up and made scalable beyond the bounds of a single server. Being limited to a single server in 2016, like Nagios was 10 years ago before they too started to split some things out, isn't something I'd advertise as a feature. I think right now Prometheus is probably filling the gap of what an industrial historian would do in a factory. It's a console you would have sitting next to the thing you were building that would provide real time measurements. We didn't want lots of individual consoles. We wanted a central large system that could hold years of historical data, as well as allowing people to query it in real time, and we liked the idea of not needing to double up on hardware costs. We're using a mix of elasticsearch and cassandra here to achieve that.
  - bbrazil 10y ago
    > Most places have no outbound port restrictions, or when they do they usually always have a proxy for traffic to go out (like https for updates etc) Depends which company. For companies that really care about security, letting arbitrary traffic out is a big no-no. Even via proxy, it requires tight controls. We've had potential users that were quite excited that Prometheus works the other way, as their network security team were likely to permit it. > There is a reason why distributed systems exist and that is to scale efficiently with some degree of redundancy baked in. The efficiency here is in humans (in theory anyway), not in resources or reliability. Distributed systems are a very hard problem, and we avoid those approaches for Prometheus as it's a critical monitoring system. CP systems like Kafka and Zookeeper are not things you want on your alerting path, as they'll fall apart when your network does. Prometheus will keep chugging along. > Single node HA is probably the most inefficient method of scaling. I'd disagree, the standard approach these days tends to be a cluster of three which'd use at least 50% more resources. > It sounds like Prometheus needs to run properly on a single box for simplicity but over time needs to be broken up and made scalable beyond the bounds of a single server. That's correct. If you manage to have enough targets inside a single datacenter (many thousands of machines), then we recommend vertical sharding first and only if that doesn't work horizontal sharding. Prometheus is really easy to run, so you'll likely end up for organisation reasons choosing to vertically sharding anyway so that each team can control their own decentralised monitoring. > We didn't want lots of individual consoles. With Grafana you can view things across many Prometheus servers. > We wanted a central large system that could hold years of historical data, Prometheus explicitly doesn't do historical data. As we're effectively talking unbounded amounts of storage that can't fit on one machine, which implies a distributed storage system. As mentioned above that's not something we want in our core for reliability. The chosen approach is that we'll interface with something else such as OpenTSDB that'll do the long term storage, and we'll support seamlessly graphing across it. That's much easier to make reliable (just add a timeout), and if it does go down you'd still have the last few weeks of data sitting on the Prometheus box. > as well as allowing people to query it in real time That we do really well, PromQL is very powerful and anything you can graph you can also alert on. > and we liked the idea of not needing to double up on hardware costs. I feel this is a bit of a red herring. The question isn't whether there's a 2X multiplier in the math, it's the overall cost as compared to the benefits. Prometheus is astoundingly efficient, the latest numbers are 800k samples/s on one machine. I haven't heard of anything else that is even close, and I believe we're also holding the record on storage efficiency. Even 10X that cost isn't likely to break the bank, so I'd suggest taking a look at the full range of features it offers and comparing to the real world cost. The operational aspects you mention are generally manageable, and if they aren't your infrastructure likely has bigger problems.

bbrazil 10y ago

> Not only that, only scaling vertically on a single node doesn't seem like a good design. For Prometheus at least, we're so efficient that it actually works out okay for the vast majority of users. You'd typically need thousands of instances doing the same thing inside a single datacenter before you get into our (admittedly more involved) horizontal sharding approach. http://www.robustperception.io/scaling-and-federating-prometheus/ http://www.robustperception.io/scaling-and-federating-promet... has more information. > There are ways to poll things and push metrics without opening millions of firewall ports to every security group. Sensu does that quite well, and it scales. I don't think that's quite a fair comparison. Sensu Just Works when there's no outbound firewall, Prometheus Just Works when there's no inbound firewall. If you add the other direction of firewall for either then things break down.

Millenis 10y ago
Hi, honestly this feels like the conversation our team had a few years ago about Nagios. Some people were happy with pockets of monitoring servers dotted around with wiki pages full of links to get to them. It took a long time to clean that up and finally end up with a single central service. The outbound vs inbound firewalls is totally a fair comparison. At almost every company I have worked for the perimeter security blocks all incoming ports. Most places have no outbound port restrictions, or when they do they usually always have a proxy for traffic to go out (like https for updates etc). This is what makes the design of outbound only connections considerably better (Sensu, Datadog, insert pretty much any SaaS vendor). I honestly don't know of any company who would open up such an extreme number of ports required to allow scraping from an external monitoring tool. In a large enterprise you want to host the monitoring tool as a service for other groups which means potentially in a totally different data center or cloud and allowing a small list of subnets 'in' is considerably better than exposing every single server to external access. For the scaling I'm not sure I totally agree. There is a reason why distributed systems exist and that is to scale efficiently with some degree of redundancy baked in. Single node HA is probably the most inefficient method of scaling. It sounds like Prometheus needs to run properly on a single box for simplicity but over time needs to be broken up and made scalable beyond the bounds of a single server. Being limited to a single server in 2016, like Nagios was 10 years ago before they too started to split some things out, isn't something I'd advertise as a feature. I think right now Prometheus is probably filling the gap of what an industrial historian would do in a factory. It's a console you would have sitting next to the thing you were building that would provide real time measurements. We didn't want lots of individual consoles. We wanted a central large system that could hold years of historical data, as well as allowing people to query it in real time, and we liked the idea of not needing to double up on hardware costs. We're using a mix of elasticsearch and cassandra here to achieve that.
- bbrazil 10y ago
  > Most places have no outbound port restrictions, or when they do they usually always have a proxy for traffic to go out (like https for updates etc) Depends which company. For companies that really care about security, letting arbitrary traffic out is a big no-no. Even via proxy, it requires tight controls. We've had potential users that were quite excited that Prometheus works the other way, as their network security team were likely to permit it. > There is a reason why distributed systems exist and that is to scale efficiently with some degree of redundancy baked in. The efficiency here is in humans (in theory anyway), not in resources or reliability. Distributed systems are a very hard problem, and we avoid those approaches for Prometheus as it's a critical monitoring system. CP systems like Kafka and Zookeeper are not things you want on your alerting path, as they'll fall apart when your network does. Prometheus will keep chugging along. > Single node HA is probably the most inefficient method of scaling. I'd disagree, the standard approach these days tends to be a cluster of three which'd use at least 50% more resources. > It sounds like Prometheus needs to run properly on a single box for simplicity but over time needs to be broken up and made scalable beyond the bounds of a single server. That's correct. If you manage to have enough targets inside a single datacenter (many thousands of machines), then we recommend vertical sharding first and only if that doesn't work horizontal sharding. Prometheus is really easy to run, so you'll likely end up for organisation reasons choosing to vertically sharding anyway so that each team can control their own decentralised monitoring. > We didn't want lots of individual consoles. With Grafana you can view things across many Prometheus servers. > We wanted a central large system that could hold years of historical data, Prometheus explicitly doesn't do historical data. As we're effectively talking unbounded amounts of storage that can't fit on one machine, which implies a distributed storage system. As mentioned above that's not something we want in our core for reliability. The chosen approach is that we'll interface with something else such as OpenTSDB that'll do the long term storage, and we'll support seamlessly graphing across it. That's much easier to make reliable (just add a timeout), and if it does go down you'd still have the last few weeks of data sitting on the Prometheus box. > as well as allowing people to query it in real time That we do really well, PromQL is very powerful and anything you can graph you can also alert on. > and we liked the idea of not needing to double up on hardware costs. I feel this is a bit of a red herring. The question isn't whether there's a 2X multiplier in the math, it's the overall cost as compared to the benefits. Prometheus is astoundingly efficient, the latest numbers are 800k samples/s on one machine. I haven't heard of anything else that is even close, and I believe we're also holding the record on storage efficiency. Even 10X that cost isn't likely to break the bank, so I'd suggest taking a look at the full range of features it offers and comparing to the real world cost. The operational aspects you mention are generally manageable, and if they aren't your infrastructure likely has bigger problems.