github.com/hashicorp/consul

IMPROVEMENTS:

• agent: Node IDs derived from host information are now hashed to prevent things like common server hardware from generating IDs with a common prefix across nodes. [GH-2884]
• agent: Added new -disable-host-node-id CLI flag and disable_host_node_id config option to the Consul agent to prevent it from using information from the host when generating a node ID. This will result in a random node ID, which is useful when running multiple Consul agents on the same host for testing purposes. Having this built-in eases configuring a random node ID when running in containers. [GH-2877]
• agent: Removed useless "==> Caught signal: broken pipe" logging since that often results from problems sending telemetry or broken incoming client connections; operators don't need to be alerted to these. [GH-2768]
• cli: Added TLS options for setting the client/CA certificates to use when communicating with Consul. These can be provided through environment variables or command line flags. [GH-2914]
• build: Consul is now built with Go 1.8.1. [GH-2888]
• ui: Updates Consul assets to new branding. [GH-2898]

BUG FIXES:

• api: Added missing Raft index fields to AgentService and Node structures. [GH-2882]
• server: Fixed an issue where flood joins would not work with IPv6 addresses. [GH-2878]
• server: Fixed an issue where electing a 0.8.x leader during an upgrade would cause a panic in older servers. [GH-2889]
• server: Fixed an issue where tracking of leadership changes could become incorrect when changes occurred very rapidly. This could manifest as a panic in Autopilot, but could have caused other issues with multiple leader management routines running simultaneously. [GH-2896]
• server: Fixed a panic when checking ACLs on a session that doesn't exist. [GH-2624]

BREAKING CHANGES:

• Command-Line Interface RPC Deprecation: The RPC client interface has been removed. All CLI commands that used RPC and the -rpc-addr flag to communicate with Consul have been converted to use the HTTP API and the appropriate flags for it, and the rpc field has been removed from the port and address binding configs. You will need to remove these fields from your config files and update any scripts that passed a custom -rpc-addr to the following commands: force-leave, info, join, keyring, leave, members, monitor, reload

• Version 8 ACLs Are Now Opt-Out: The acl_enforce_version_8 configuration now defaults to true to enable full version 8 ACL support by default. If you are upgrading an existing cluster with ACLs enabled, you will need to set this to false during the upgrade on both Consul agents and Consul servers. Version 8 ACLs were also changed so that acl_datacenter must be set on agents in order to enable the agent-side enforcement of ACLs. This makes for a smoother experience in clusters where ACLs aren't enabled at all, but where the agents would have to wait to contact a Consul server before learning that. [GH-2844]

• Remote Exec Is Now Opt-In: The default for disable_remote_exec was changed to "true", so now operators need to opt-in to having agents support running commands remotely via consul exec. [GH-2854]

• Raft Protocol Compatibility: When upgrading to Consul 0.8.0 from a version lower than 0.7.0, users will need to set the -raft-protocol option to 1 in order to maintain backwards compatibility with the old servers during the upgrade. See Upgrading Specific Versions guide for more details.

FEATURES:

• Autopilot: A set of features has been added to allow for automatic operator-friendly management of Consul servers. For more information about Autopilot, see the Autopilot Guide.
  • Dead Server Cleanup: Dead servers will periodically be cleaned up and removed from the Raft peer set, to prevent them from interfering with the quorum size and leader elections.
  • Server Health Checking: An internal health check has been added to track the stability of servers. The thresholds of this health check are tunable as part of the Autopilot configuration and the status can be viewed through the /v1/operator/autopilot/health HTTP endpoint.
  • New Server Stabilization: When a new server is added to the cluster, there will be a waiting period where it must be healthy and stable for a certain amount of time before being promoted to a full, voting member. This threshold can be configured using the new server_stabilization_time setting.
  • Advanced Redundancy: (Consul Enterprise) A new -non-voting-server option flag has been added for Consul servers to configure a server that does not participate in the Raft quorum. This can be used to add read scalability to a cluster in cases where a high volume of reads to servers are needed, but non-voting servers can be lost without causing an outage. There's also a new redundancy_zone_tag configuration that allows Autopilot to manage separating servers into zones for redundancy. Only one server in each zone can be a voting member at one time. This helps when Consul servers are managed with automatic replacement with a system like a resource scheduler or auto-scaling group. Extra non-voting servers in each zone will be available as hot standbys (that help with read-scaling) that can be quickly promoted into service when the voting server in a zone fails.
  • Upgrade Orchestration: (Consul Enterprise) Autopilot will automatically orchestrate an upgrade strategy for Consul servers where it will initially add newer versions of Consul servers as non-voters, wait for a full set of newer versioned servers to be added, and then gradually swap into service as voters and swap out older versioned servers to non-voters. This allows operators to safely bring up new servers, wait for the upgrade to be complete, and then terminate the old servers.
• Network Areas: (Consul Enterprise) A new capability has been added which allows operators to define network areas that join together two Consul datacenters. Unlike Consul's WAN feature, network areas use just the server RPC port for communication, and pairwise relationships can be made between arbitrary datacenters, so not all servers need to be fully connected. This allows for complex topologies among Consul datacenters like hub/spoke and more general trees. See the Network Areas Guide for more details.
• WAN Soft Fail: Request routing between servers in the WAN is now more robust by treating Serf failures as advisory but not final. This means that if there are issues between some subset of the servers in the WAN, Consul will still be able to route RPC requests as long as RPCs are actually still working. Prior to WAN Soft Fail, any datacenters having connectivity problems on the WAN would mean that all DCs might potentially stop sending RPCs to those datacenters. [GH-2801]
• WAN Join Flooding: A new routine was added that looks for Consul servers in the LAN and makes sure that they are joined into the WAN as well. This catches up up newly-added servers onto the WAN as soon as they join the LAN, keeping them in sync automatically. [GH-2801]
• Validate command: To provide consistency across our products, the configtest command has been deprecated and replaced with the validate command (to match Nomad and Terraform). The configtest command will be removed in Consul 0.9. [GH-2732]

IMPROVEMENTS:

• agent: Fixed a missing case where gossip would stop flowing to dead nodes for a short while. [GH-2722]
• agent: Changed agent to seed Go's random number generator. [GH-2722]
• agent: Serf snapshots no longer have the executable bit set on the file. [GH-2722]
• agent: Consul is now built with Go 1.8. [GH-2752]
• agent: Updated aws-sdk-go version (used for EC2 auto join) for Go 1.8 compatibility. [GH-2755]
• agent: User-supplied node IDs are now normalized to lower-case. [GH-2798]
• agent: Added checks to enforce uniqueness of agent node IDs at cluster join time and when registering with the catalog. [GH-2832]
• cli: Standardized handling of CLI options for connecting to the Consul agent. This makes sure that the same set of flags and environment variables works in all CLI commands (see https://developer.hashicorp.com/docs/commands/index.html#environment-variables). [GH-2717]
• cli: Updated go-cleanhttp library for better HTTP connection handling between CLI commands and the Consul agent (tunes reuse settings). [GH-2735]
• cli: The operator raft subcommand has had its two modes split into the list-peers and remove-peer subcommands. The old flags for these will continue to work for backwards compatibility, but will be removed in Consul 0.9.
• cli: Added an -id flag to the operator raft remove-peer command to allow removing a peer by ID. [GH-2847]
• dns: Allows the .service tag to be optional in RFC 2782 lookups. [GH-2690]
• server: Changed the internal EnsureRegistration RPC endpoint to prevent registering checks that aren't associated with the top-level node being registered. [GH-2846]

BUG FIXES:

• agent: Fixed an issue with consul watch not working when http was listening on a unix socket. [GH-2385]
• agent: Fixed an issue where checks and services could not sync deregister operations back to the catalog when version 8 ACL support is enabled. [GH-2818]
• agent: Fixed an issue where agents could use the ACL token registered with a service when registering checks for the same service that were registered with a different ACL token. [GH-2829]
• cli: Fixed consul kv commands not reading the CONSUL_HTTP_TOKEN environment variable. [GH-2566]
• cli: Fixed an issue where prefixing an address with a protocol (such as 'http://' or 'https://') in -http-addr or CONSUL_HTTP_ADDR would give an error.
• cli: Fixed an issue where error messages would get printed to stdout instead of stderr. [GH-2548]
• server: Fixed an issue with version 8 ACLs where servers couldn't deregister nodes from the catalog during reconciliation. [GH-2792] This fix was generalized and applied to registering nodes as well. [GH-2826]
• server: Fixed an issue where servers could temporarily roll back changes to a node's metadata or tagged addresses when making updates to the node's health checks. [GH-2826]
• server: Fixed an issue where the service name consul was not subject to service ACL policies with version 8 ACLs enabled. [GH-2816]