+1 from me (stumbled across this while setup of cluster mode in k8s) i think we could leave the resolution or dns caching to the underlying os.
Julian Holen Sie sich Outlook für Android<https://aka.ms/ghei36> ________________________________ From: Xiangdong Huang <[email protected]> Sent: Friday, August 27, 2021 7:30:22 AM To: dev <[email protected]> Subject: Re: discuss why we have to replace hostname to ip in the cluster module yes, my viewpoint is the same, hostname or IP has no difference for IoTDB. The core is, we need to use node identifiers to distinguish nodes. Best, ----------------------------------- Xiangdong Huang School of Software, Tsinghua University 黄向东 清华大学 软件学院 Houliang Qi <[email protected]> 于2021年8月27日周五 下午1:23写道： > > Hi, Xiangdong > > > > I do not think we will abandon using IP. Either using IP or hostname > > depends on users. If they are sure they have a good DNS, they can use DNS; > > If they like IP or the nodes do not set the DNS, they can use IP. If they > > like, they can also mix-use the hostname and IP addresses. We do not need > > to care….. > > > As mentioned above, since users can use either IP or hostname, I don't > realize what the focus of this discussion is. I think the focus is on what > the user manual is exposed to the user? What are the functions provided? As > for the implementation of the code, I think it is OK to use hostname or IP. > > > In the k8s cluster, the hostname of some pods is also changed. If we only > replace IP with hostname, it will not make our iotdb run perfectly on k8s. > Therefore, I think it is not important to use hostname or IP. The important > thing is to realize the function of automatic service maintenance that can be > deployed on k8s. > > > Thanks, > --------------------------------------- > Houliang Qi > BONC, Ltd > On 08/26/2021 18:29，Xiangdong Huang<[email protected]> wrote： > Hi, > > DNS request is an additional cost in nodes communication. > > I do not think we will abandon using IP. Either using IP or hostname > depends on users. > If they are sure they have a good DNS, they can use DNS; > If they like IP or the nodes do not set the DNS, they can use IP. > If they like, they can also mix-use the hostname and IP addresses. We > do not need to care..... > > We should make the relationship between node IP, node hostname and node > identifier be clear. > > IMO, node identifier is the only option. > > Best, > ----------------------------------- > Xiangdong Huang > School of Software, Tsinghua University > > 黄向东 > 清华大学 软件学院 > > Eric Pai <[email protected]> 于2021年8月26日周四 下午4:46写道： > > Hi, Xiangdong, > > Supporting hostname is really a good feature! However, we should consider > these cons carefully: > > 1. DNS request is an additional cost in nodes communication. In cloud > environment, the latency may be as large as hundreds of milliseconds(e.g. > across available regions), and local DNS cache is also an issue in some > extreme scenarios. > 2. We should make the relationship between node IP, node hostname and node > identifier be clear. A node should not be treated as a new one if it changes > its IP or hostname. Or allowing to change IP only. > > 在 2021/8/25 下午11:15，“Xiangdong Huang”<[email protected]> 写入: > > Hi, > > Today Julian and I discussed some logic of the cluster module. > Both of us feel it strange that we replace the hostname to IP before a > cluster node starts up. > I think it is not a very common way. > > hostname sometimes is very very helpful. For example, in K8S > environment, a node's hostname never changes, but its IP may change. > > Best, > ----------------------------------- > Xiangdong Huang > School of Software, Tsinghua University > > 黄向东 > 清华大学 软件学院 >
