HADOOP-13190. Mention LoadBalancingKMSClientProvider in KMS HA documentation. Contributed by Wei-Chiu Chuang.
Project: http://git-wip-us.apache.org/repos/asf/hadoop/repo Commit: http://git-wip-us.apache.org/repos/asf/hadoop/commit/db719ef1 Tree: http://git-wip-us.apache.org/repos/asf/hadoop/tree/db719ef1 Diff: http://git-wip-us.apache.org/repos/asf/hadoop/diff/db719ef1 Branch: refs/heads/HADOOP-13345 Commit: db719ef125b11b01eab3353e2dc4b48992bf88d5 Parents: d892ae9 Author: Wei-Chiu Chuang <weic...@apache.org> Authored: Thu Aug 11 12:27:09 2016 -0700 Committer: Wei-Chiu Chuang <weic...@apache.org> Committed: Thu Aug 11 12:27:09 2016 -0700 ---------------------------------------------------------------------- .../hadoop-kms/src/site/markdown/index.md.vm | 66 +++++++++++++++++--- 1 file changed, 59 insertions(+), 7 deletions(-) ---------------------------------------------------------------------- http://git-wip-us.apache.org/repos/asf/hadoop/blob/db719ef1/hadoop-common-project/hadoop-kms/src/site/markdown/index.md.vm ---------------------------------------------------------------------- diff --git a/hadoop-common-project/hadoop-kms/src/site/markdown/index.md.vm b/hadoop-common-project/hadoop-kms/src/site/markdown/index.md.vm index d50b0f4..889dbaf1 100644 --- a/hadoop-common-project/hadoop-kms/src/site/markdown/index.md.vm +++ b/hadoop-common-project/hadoop-kms/src/site/markdown/index.md.vm @@ -19,6 +19,8 @@ Hadoop Key Management Server (KMS) - Documentation Sets ======================================================= +<!-- MACRO{toc|fromDepth=0|toDepth=3} --> + Hadoop KMS is a cryptographic key management server based on Hadoop's **KeyProvider** API. It provides a client and a server components which communicate over HTTP using a REST API. @@ -34,6 +36,18 @@ KMS Client Configuration The KMS client `KeyProvider` uses the **kms** scheme, and the embedded URL must be the URL of the KMS. For example, for a KMS running on `http://localhost:9600/kms`, the KeyProvider URI is `kms://http@localhost:9600/kms`. And, for a KMS running on `https://localhost:9600/kms`, the KeyProvider URI is `kms://https@localhost:9600/kms` +The following is an example to configure HDFS NameNode as a KMS client in +`hdfs-site.xml`: + + <property> + <name>dfs.encryption.key.provider.uri</name> + <value>kms://http@localhost:9600/kms</value> + <description> + The KeyProvider to use when interacting with encryption keys used + when reading and writing to an encryption zone. + </description> + </property> + KMS --- @@ -623,13 +637,51 @@ Additionally, KMS delegation token secret manager can be configured with the fol </property> ``` -$H3 Using Multiple Instances of KMS Behind a Load-Balancer or VIP - -KMS supports multiple KMS instances behind a load-balancer or VIP for scalability and for HA purposes. - -When using multiple KMS instances behind a load-balancer or VIP, requests from the same user may be handled by different KMS instances. - -KMS instances behind a load-balancer or VIP must be specially configured to work properly as a single logical service. +$H3 High Availability + +Multiple KMS instances may be used to provide high availability and scalability. +Currently there are two approaches to supporting multiple KMS instances: +running KMS instances behind a load-balancer/VIP, +or using LoadBalancingKMSClientProvider. + +In both approaches, KMS instances must be specially configured to work properly +as a single logical service, because requests from the same client may be +handled by different KMS instances. In particular, +Kerberos Principals Configuration, HTTP Authentication Signature and Delegation +Tokens require special attention. + +$H4 Behind a Load-Balancer or VIP + +Because KMS clients and servers communicate via a REST API over HTTP, +Load-balancer or VIP may be used to distribute incoming traffic to achieve +scalability and HA. In this mode, clients are unaware of multiple KMS instances +at the server-side. + +$H4 Using LoadBalancingKMSClientProvider + +An alternative to running multiple KMS instances behind a load-balancer or VIP, +is to use LoadBalancingKMSClientProvider. Using this approach, a KMS client +(for example, a HDFS NameNode) is aware of multiple KMS instances, and it sends +requests to them in a round-robin fashion. LoadBalancingKMSClientProvider is +implicitly used when more than one URI is specified in +`dfs.encryption.key.provider.uri`. + +The following example in `hdfs-site.xml` configures two KMS +instances, `kms01.example.com` and `kms02.example.com`. +The hostnames are separated by semi-colons, and all KMS instances must run +on the same port. + + <property> + <name>dfs.encryption.key.provider.uri</name> + <value>kms://ht...@kms01.example.com;kms02.example.com:9600/kms</value> + <description> + The KeyProvider to use when interacting with encryption keys used + when reading and writing to an encryption zone. + </description> + </property> + +If a request to a KMS instance fails, clients retry with the next instance. The +request is returned as failure only if all instances fail. $H4 HTTP Kerberos Principals Configuration --------------------------------------------------------------------- To unsubscribe, e-mail: common-commits-unsubscr...@hadoop.apache.org For additional commands, e-mail: common-commits-h...@hadoop.apache.org
