72 lines
2.4 KiB
Markdown
72 lines
2.4 KiB
Markdown
---
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title: Adding and Removing Hosts Dynamically
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menu_order: 90
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---
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To add a host to an existing Weave network, launch Weave Net on the
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host, and supply the address of at least one host. Weave Net
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automatically discovers any other hosts in the network and establishes
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connections with them if it can (in order to avoid unnecessary
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multi-hop routing).
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In some situations existing Weave Net hosts may be unreachable from
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the new host due to firewalls, etc. However, it is still possible to
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add the new host, provided that inverse connections, for example, from
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existing hosts to the new hosts, are available.
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To accomplish this, launch Weave Net onto the new host without
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supplying any additional addresses and then, from one of the existing
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hosts run:
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host# weave connect $NEW_HOST
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Any other existing hosts on the Weave network will attempt to
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establish connections to the new host as well.
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###Instructing Peers to Forget a Host
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To instruct a peer to forget a particular host specified to it via
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`weave launch` or `weave connect` run:
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host# weave forget $DECOMMISSIONED_HOST
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This prevents the peer from reconnecting to that host once
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connectivity to it is lost, and can be used to administratively remove
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any decommissioned peers from the network.
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###Bulk Replacing Hosts
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Hosts can also be bulk-replaced. All existing hosts will be forgotten,
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and the new hosts added:
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host# weave connect --replace $NEW_HOST1 $NEW_HOST2
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###Restarting Docker and Weave Net
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If Weave Net is restarted by Docker it automatically remembers any
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previous connect and forget operations, however if you stop it
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manually and launch it again, it will not remember any prior connects.
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If you want to launch again and retain the results of those operations
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use `--resume`:
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host# weave launch --resume
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> **Note:** In this case, you cannot specify a list of addresses,
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> since the previous peer list is used exclusively.
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For complete control over the peer topology, disable automatic
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discovery using the `--no-discovery` option with `weave launch`.
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If discovery if disabled, Weave Net only connects to the addresses
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specified at launch time and with `weave connect`.
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To return a list of all hosts and their peer connections established
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with `weave launch` and `weave connect` run:
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host# weave status targets
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**See Also**
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* [Enabling Multi-Cloud, Multi-Hop Networking and Routing](/site/using-weave/multi-cloud-multi-hop.md)
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* [Stopping and Removing Peers](/site/ipam/stop-remove-peers-ipam.md)
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