Thanks a lot, Jason! Answers inline. I'll also modify the kip to make these clear.
On Fri, Sep 6, 2019 at 4:01 PM Jason Gustafson <ja...@confluent.io> wrote: > Hi Arjun, > > The updated KIP looks good. Just a couple questions: > > 1. Is the /admin endpoint on the normal listener by default? If not, is > there a way to have it use the same listener? > Uses the normal listener by default. > 2. Changes to logging configuration are not intended to be persistent, is > that right? Also, I assume changes only apply to the worker that received > the request? > Changes will not be persistent and only apply to the worker that received the request. > Thanks, > Jason > > On Fri, Aug 30, 2019 at 1:25 AM Arjun Satish <arjun.sat...@gmail.com> > wrote: > > > OK. I didn't realize the plan was to deprecate and remove the JMX > endpoint. > > KIP-412 says brokers will continue to expose the JMX API. JMX was > selected > > so all components could follow the brokers. In light of this, I think we > > should simply aim for semantic equivalency across the different API for > > this functionality. > > > > REST is convenient for Connect. We can modify the KIP to have a /admin > > endpoint, and /admin/loggers specifically for getting/setting the log > > levels of different loggers. The /admin/loggers will only impact loggers > > running in the specific worker we target requests to, and upon restarting > > the worker, these loggers will reset back to their original level. > > > > Since configuring the rest server already has multiple config keys, I am > > inclined to bundle this /admin endpoint on to the same listener, and > > provide a single new config key that enables or disables the entire > /admin > > endpoint. This keeps the initial approach simple and doesn't require > users > > to configure/discover a new endpoint. > > > > If this works with you all, I can update the KIP. Please let me know what > > you think. > > > > Thanks everyone. > > > > Best, > > > > On Thu, Aug 29, 2019 at 10:14 AM Colin McCabe <cmcc...@apache.org> > wrote: > > > > > On Mon, Aug 26, 2019, at 14:03, Jason Gustafson wrote: > > > > Hi Arjun, > > > > > > > > From a high level, I feel like we are making light of the JMX api > > because > > > > it's convenient and the broker already has it. Personally I would > take > > > the > > > > broker out of the picture. The JMX endpoint is not something we were > > > happy > > > > with, hence KIP-412. Ultimately I think we will deprecate and remove > it > > > and > > > > there's no point trying to standardize on a deprecated mechanism. > > > Thinking > > > > just about connect, we already have an HTTP endpoint. The default > > > position > > > > should be to add new APIs to it rather than introducing other > > mechanisms. > > > > The fewer ways you have to interact with a system, the better, right? > > > > > > > > I think the main argument against a REST endpoint is basically that > > > > adjusting log levels is an administrative operation and connect is > > > lacking > > > > an authorization framework to enforce administrative access. The same > > > > argument applies to JMX, but it has the benefit that you can specify > > > > different credentials and it is easier to isolate since it is running > > on > > > a > > > > separate port. As you suggested, I think the same benefits could be > > > > achieved by having a separate /admin endpoint which is exposed > (perhaps > > > > optionally) on another listener. This is a pretty standard pattern. > If > > > > memory serves, dropwizard has something like this out of the box. We > > > should > > > > think hard whether there are additional administrative capabilities > > that > > > we > > > > would ultimately need. The answer is probably yes, so unless we want > to > > > > double down on JMX, it might be worth thinking through the > implications > > > of > > > > an admin endpoint now so that we're not left with odd compatibility > > > baggage > > > > in the future. > > > > > > Hi Jason, > > > > > > I agree... I think Connect needs a REST admin API. There will probably > > be > > > a lot of other stuff that we'll want to add to it. > > > > > > best, > > > Colin > > > > > > > > > > > > > > Thanks, > > > > Jason > > > > > > > > > > > > > > > > > > > > On Fri, Aug 23, 2019 at 5:38 PM Arjun Satish <arjun.sat...@gmail.com > > > > > wrote: > > > > > > > > > Jason, > > > > > > > > > > Thanks for your comments! > > > > > > > > > > I understand the usability issues with JMX that you mention. But it > > was > > > > > chosen for the following reasons: > > > > > > > > > > 1. Cross-cutting functionality across different components (Kafka > > > brokers, > > > > > Connect workers and even with Streams jobs). If we go down the REST > > > route, > > > > > then brokers don't get this feature. > > > > > 2. Adding this to existing REST servers adds the whole-or-nothing > > > problem. > > > > > It's hard to disable an endpoint if the functionality is not > desired > > or > > > > > needs to be protected from users (Connect doesn't have ACLs which > > makes > > > > > this even harder to manage). Adding endpoints to different > listeners > > > makes > > > > > configuring Connect harder (and it's already a hard problem as it > > is). > > > A > > > > > lot of the existing functionality there is driven around the > > connector > > > data > > > > > model (connectors, plugins, their statuses and so on). Adding an > > > '/admin' > > > > > endpoint may be a way to go, but that has tremendous implications > (we > > > are > > > > > effectively adding an administration endpoint similar to the admin > > one > > > in > > > > > brokers), and probably requires a KIP of its own with discussions > > > catered > > > > > around just that. > > > > > 3. JMX is currently AK's default way to report metrics and perform > > > other > > > > > operations. Changing log levels is typically a system level/admin > > > > > operation, and fits better there, instead of REST APIs (which is > more > > > user > > > > > facing). > > > > > > > > > > Having said that, I'm happy to consider alternatives. JMX seemed to > > be > > > the > > > > > lowest hanging fruit. But if there are better ideas, we can > consider > > > them. > > > > > At the end of the day, when we download and run Kafka, there should > > be > > > one > > > > > way to achieve the same functionality among its components. > > > > > > > > > > Finally, I hope I didn't convey that we are reverting/changing the > > > changes > > > > > made in KIP-412. The proposed changes would be an addition to it. > It > > > will > > > > > give brokers multiple ways of changing log levels. and there is > > still a > > > > > consistent way of achieving cross component goals of the KIP. > > > > > > > > > > Best, > > > > > > > > > > > > > > > On Fri, Aug 23, 2019 at 4:12 PM Jason Gustafson < > ja...@confluent.io> > > > > > wrote: > > > > > > > > > > > Let me elaborate a little bit. We made the decision early on for > > > Connect > > > > > to > > > > > > use HTTP instead of Kafka's custom RPC protocol. In exchange for > > > losing > > > > > > some hygienic consistency with Kafka, we took easier integration > > with > > > > > > management tools. The scope of the connect REST APIs is really > > > managing > > > > > the > > > > > > connect cluster. It has endpoints for creating connectors, > changing > > > > > > configs, seeing their health, etc. Doesn't debugging fit in with > > > that? I > > > > > am > > > > > > not sure I see why we would treat this as an exceptional case. > > > > > > > > > > > > I personally see JMX as a necessary evil in Kafka because most > > > metrics > > > > > > agents have native support. But it is particularly painful when > it > > > comes > > > > > to > > > > > > use as an RPC mechanism. This was the central motivation behind > > > KIP-412, > > > > > > which makes it very odd to see a new proposal which suggests > > > > > standardizing > > > > > > on JMX for log level adjustment. I actually see this as something > > > we'd > > > > > want > > > > > > to eventually turn off in Kafka. Now that we have a proper API > with > > > > > support > > > > > > in the AdminClient, we can deprecate and eventually remove the > JMX > > > > > > endpoint. > > > > > > > > > > > > Thanks, > > > > > > Jason > > > > > > > > > > > > On Fri, Aug 23, 2019 at 10:49 AM Jason Gustafson < > > ja...@confluent.io > > > > > > > > > > wrote: > > > > > > > > > > > > > Hi Arjun, > > > > > > > > > > > > > > Thanks for the KIP. Do we really need a JMX-based API? Is there > > > > > literally > > > > > > > anyone in the world that wants to use JMX if they don't have > to? > > I > > > > > > thought > > > > > > > one of the major motivations of KIP-412 was how much of a pain > > JMX > > > is. > > > > > > > > > > > > > > Thanks, > > > > > > > Jason > > > > > > > > > > > > > > On Mon, Aug 19, 2019 at 5:28 PM Arjun Satish < > > > arjun.sat...@gmail.com> > > > > > > > wrote: > > > > > > > > > > > > > >> Thanks, Konstantine. > > > > > > >> > > > > > > >> Updated the KIP with the restrictions around log4j and added > > > > > references > > > > > > to > > > > > > >> similar KIPs. > > > > > > >> > > > > > > >> Best, > > > > > > >> > > > > > > >> On Mon, Aug 19, 2019 at 3:20 PM Konstantine Karantasis < > > > > > > >> konstant...@confluent.io> wrote: > > > > > > >> > > > > > > >> > Thanks Arjun, the example is useful! > > > > > > >> > > > > > > > >> > My point when I mentioned the restrictions around log4j is > > that > > > this > > > > > > is > > > > > > >> > information is significant and IMO needs to be included in > the > > > KIP. > > > > > > >> > > > > > > > >> > Speaking of its relevance to KIP-412, I think a reference > > would > > > be > > > > > > nice > > > > > > >> > too. > > > > > > >> > > > > > > > >> > Konstantine > > > > > > >> > > > > > > > >> > > > > > > > >> > > > > > > > >> > On Thu, Aug 15, 2019 at 4:00 PM Arjun Satish < > > > > > arjun.sat...@gmail.com> > > > > > > >> > wrote: > > > > > > >> > > > > > > > >> > > Hey Konstantine, > > > > > > >> > > > > > > > > >> > > Thanks for the feedback. > > > > > > >> > > > > > > > > >> > > re: the use of log4j, yes, the proposed changes will only > > > work if > > > > > > >> log4j > > > > > > >> > is > > > > > > >> > > available in runtime. We will not add the mBean if log4j > is > > > not > > > > > > >> available > > > > > > >> > > in classpath. If we change from log4j 1 to 2, that would > > > involve > > > > > > >> another > > > > > > >> > > KIP, and it would need to update the changes proposed in > > this > > > KIP > > > > > > and > > > > > > >> > > others (KIP-412, for instance). > > > > > > >> > > > > > > > > >> > > re: use of Object types, I've changed it from Boolean to > the > > > > > > primitive > > > > > > >> > type > > > > > > >> > > for setLogLevel. We are changing the signature of the old > > > method > > > > > > this > > > > > > >> > way, > > > > > > >> > > but since it never returned null, this should be fine. > > > > > > >> > > > > > > > > >> > > re: example usage, I've added some screenshot on how this > > > feature > > > > > > >> would > > > > > > >> > be > > > > > > >> > > used with jconsole. > > > > > > >> > > > > > > > > >> > > Hope this works! > > > > > > >> > > > > > > > > >> > > Thanks very much, > > > > > > >> > > Arjun > > > > > > >> > > > > > > > > >> > > On Wed, Aug 14, 2019 at 6:42 AM Konstantine Karantasis < > > > > > > >> > > konstant...@confluent.io> wrote: > > > > > > >> > > > > > > > > >> > > > And one thing I forgot is also related to Chris's > comment > > > > > above. I > > > > > > >> > agree > > > > > > >> > > > that an example on how a user is expected to set the log > > > level > > > > > > (for > > > > > > >> > > > instance to DEBUG) would be nice, even if it's showing > > only > > > one > > > > > > out > > > > > > >> of > > > > > > >> > > the > > > > > > >> > > > many possible ways to achieve that. > > > > > > >> > > > > > > > > > >> > > > - Konstantine > > > > > > >> > > > > > > > > > >> > > > On Wed, Aug 14, 2019 at 4:38 PM Konstantine Karantasis < > > > > > > >> > > > konstant...@confluent.io> wrote: > > > > > > >> > > > > > > > > > >> > > > > > > > > > > >> > > > > Thanks Arjun for tackling the need to support this > very > > > useful > > > > > > >> > feature. > > > > > > >> > > > > > > > > > > >> > > > > One thing I noticed while reading the KIP is that I > > would > > > have > > > > > > >> loved > > > > > > >> > to > > > > > > >> > > > > see more info regarding how this proposal depends on > the > > > > > > >> underlying > > > > > > >> > > > logging > > > > > > >> > > > > APIs and implementations. For instance, my > understanding > > > is > > > > > that > > > > > > >> > slf4j > > > > > > >> > > > can > > > > > > >> > > > > not be leveraged and that the logging framework needs > to > > > be > > > > > > >> pegged to > > > > > > >> > > > log4j > > > > > > >> > > > > explicitly (or another logging implementation). > Correct > > > me if > > > > > > I'm > > > > > > >> > > wrong, > > > > > > >> > > > > but if such a dependency is introduced I believe it's > > > worth > > > > > > >> > mentioning. > > > > > > >> > > > > > > > > > > >> > > > > Additionally, if the above is correct, there are > > > differences > > > > > in > > > > > > >> > log4j's > > > > > > >> > > > > APIs between version 1 and version 2. In version 2, > > > > > > >> Logger#setLevel > > > > > > >> > > > method > > > > > > >> > > > > has been removed from the Logger interface and in > order > > > to set > > > > > > the > > > > > > >> > log > > > > > > >> > > > > level programmatically the Configurator class needs to > > > used, > > > > > > >> which as > > > > > > >> > > > > stated in the FAQ ( > > > > > > >> > > > > > > > > > > >> > > > > > > > > > > https://logging.apache.org/log4j/2.x/faq.html#reconfig_level_from_code > > > > > > >> > > ) > > > > > > >> > > > > it's not part of log4j2's public API. Is this a > > concern? I > > > > > > believe > > > > > > >> > that > > > > > > >> > > > > even if these are implementation specific details for > > the > > > > > > wrappers > > > > > > >> > > > > introduced by this KIP (which to a certain extent they > > > are), a > > > > > > >> > mention > > > > > > >> > > in > > > > > > >> > > > > the KIP text and a few references would be useful to > > > > > understand > > > > > > >> the > > > > > > >> > > > changes > > > > > > >> > > > > and the dependencies introduced by this proposal. > > > > > > >> > > > > > > > > > > >> > > > > And a few minor comments: > > > > > > >> > > > > - Is there any specific reason that object types were > > > > > preferred > > > > > > in > > > > > > >> > the > > > > > > >> > > > > proposed interface compared to primitive types? My > > > > > understanding > > > > > > >> is > > > > > > >> > > that > > > > > > >> > > > > `null` is not expected as a return value. > > > > > > >> > > > > - Related to the above, I think it'd be nice for the > > > javadoc > > > > > to > > > > > > >> > mention > > > > > > >> > > > > when a parameter is not expected to be `null` with an > > > > > > appropriate > > > > > > >> > > comment > > > > > > >> > > > > (e.g. foo bar etc; may not be null) > > > > > > >> > > > > > > > > > > >> > > > > Cheers, > > > > > > >> > > > > Konstantine > > > > > > >> > > > > > > > > > > >> > > > > On Tue, Aug 6, 2019 at 9:34 AM Cyrus Vafadari < > > > > > > cy...@confluent.io > > > > > > >> > > > > > > > >> > > > wrote: > > > > > > >> > > > > > > > > > > >> > > > >> This looks like a useful feature, the strategy makes > > > sense, > > > > > and > > > > > > >> the > > > > > > >> > > KIP > > > > > > >> > > > is > > > > > > >> > > > >> thorough and nicely written. Thanks! > > > > > > >> > > > >> > > > > > > >> > > > >> Cyrus > > > > > > >> > > > >> > > > > > > >> > > > >> On Thu, Aug 1, 2019, 12:40 PM Chris Egerton < > > > > > > chr...@confluent.io > > > > > > >> > > > > > > > >> > > > wrote: > > > > > > >> > > > >> > > > > > > >> > > > >> > Thanks Arjun! Looks good to me. > > > > > > >> > > > >> > > > > > > > >> > > > >> > On Thu, Aug 1, 2019 at 12:33 PM Arjun Satish < > > > > > > >> > > arjun.sat...@gmail.com> > > > > > > >> > > > >> > wrote: > > > > > > >> > > > >> > > > > > > > >> > > > >> > > Thanks for the feedback, Chris! > > > > > > >> > > > >> > > > > > > > > >> > > > >> > > Yes, the example is pretty much how Connect will > > use > > > the > > > > > > new > > > > > > >> > > > feature. > > > > > > >> > > > >> > > Tweaked the section to make this more clear. > > > > > > >> > > > >> > > > > > > > > >> > > > >> > > Best, > > > > > > >> > > > >> > > > > > > > > >> > > > >> > > On Fri, Jul 26, 2019 at 11:52 AM Chris Egerton < > > > > > > >> > > chr...@confluent.io > > > > > > >> > > > > > > > > > > >> > > > >> > > wrote: > > > > > > >> > > > >> > > > > > > > > >> > > > >> > > > Hi Arjun, > > > > > > >> > > > >> > > > > > > > > > >> > > > >> > > > This looks great. The changes to public > interface > > > are > > > > > > >> pretty > > > > > > >> > > small > > > > > > >> > > > >> and > > > > > > >> > > > >> > > > moving the Log4jController class into the > clients > > > > > package > > > > > > >> > seems > > > > > > >> > > > like > > > > > > >> > > > >> > the > > > > > > >> > > > >> > > > right way to go. One question I have--it looks > > > like the > > > > > > >> > purpose > > > > > > >> > > of > > > > > > >> > > > >> this > > > > > > >> > > > >> > > KIP > > > > > > >> > > > >> > > > is to enable dynamic setting of log levels in > the > > > > > Connect > > > > > > >> > > > framework, > > > > > > >> > > > >> > but > > > > > > >> > > > >> > > > it's not clear how the Connect framework will > use > > > that > > > > > > new > > > > > > >> > > > utility. > > > > > > >> > > > >> Is > > > > > > >> > > > >> > > the > > > > > > >> > > > >> > > > "Example Usage" section (which involves > invoking > > > the > > > > > > >> utility > > > > > > >> > > with > > > > > > >> > > > a > > > > > > >> > > > >> > > > namespace of "kafka.connect") actually meant to > > be > > > part > > > > > > of > > > > > > >> the > > > > > > >> > > > >> proposed > > > > > > >> > > > >> > > > changes to public interface? > > > > > > >> > > > >> > > > > > > > > > >> > > > >> > > > Cheers, > > > > > > >> > > > >> > > > > > > > > > >> > > > >> > > > Chris > > > > > > >> > > > >> > > > > > > > > > >> > > > >> > > > On Mon, Jul 22, 2019 at 11:03 PM Arjun Satish < > > > > > > >> > > > >> arjun.sat...@gmail.com> > > > > > > >> > > > >> > > > wrote: > > > > > > >> > > > >> > > > > > > > > > >> > > > >> > > > > Hi everyone. > > > > > > >> > > > >> > > > > > > > > > > >> > > > >> > > > > I'd like to propose the following KIP to > > > implement > > > > > > >> changing > > > > > > >> > > log > > > > > > >> > > > >> > levels > > > > > > >> > > > >> > > on > > > > > > >> > > > >> > > > > the fly in Connect workers: > > > > > > >> > > > >> > > > > > > > > > > >> > > > >> > > > > > > > > > > >> > > > >> > > > > > > > > > > >> > > > >> > > > > > > > > > >> > > > >> > > > > > > > > >> > > > >> > > > > > > > >> > > > >> > > > > > > >> > > > > > > > > > >> > > > > > > > > >> > > > > > > > >> > > > > > > > > > > > > > > > > > https://cwiki.apache.org/confluence/display/KAFKA/KIP-495%3A+Dynamically+Adjust+Log+Levels+in+Connect > > > > > > >> > > > >> > > > > > > > > > > >> > > > >> > > > > Would like to hear your thoughts on this. > > > > > > >> > > > >> > > > > > > > > > > >> > > > >> > > > > Thanks very much, > > > > > > >> > > > >> > > > > Arjun > > > > > > >> > > > >> > > > > > > > > > > >> > > > >> > > > > > > > > > >> > > > >> > > > > > > > > >> > > > >> > > > > > > > >> > > > >> > > > > > > >> > > > > > > > > > > >> > > > > > > > > > >> > > > > > > > > >> > > > > > > > >> > > > > > > > > > > > > > > > > > > > > > > > > > > > >
