82 lines
4.5 KiB
Markdown
82 lines
4.5 KiB
Markdown
# Albatross: orchestrate and manage MirageOS unikernels with Solo5
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[](https://travis-ci.org/hannesm/albatross)
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The goal of albatross is robust deployment of [MirageOS](https://mirage.io)
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unikernels using [Solo5](https://github.com/solo5/solo5), including precise
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error handling of failures. The code running under superuser privileges is
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minimimal. Albatross is supposed to be run on a machine in the dom0, next to the
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hypervisor. Albatross keeps track of unikernel resource usage (memory, CPUs,
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bridges, block storage and active block devices). Policies restricting these
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resources for administrative domains are available. Local and remote deployments
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are supported, remote ones are authenticated and encrypted via a mutually
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authenticated TLS connection using X.509 client certificates. Multi-tenancy
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deployments are possible, tenants do not need any other access to the machine:
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console output and statistics gathered by the host are accessible via TLS.
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Albatross keeps the information of running unikernels persistently, and starts
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these unikernels when the albatross daemon is started. This means that whenever
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a unikernel was started, it keeps running until it crashes or an explicit
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destroy command is issued.
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The administrative domain is similar to DNS: each unikernel has a name (e.g.
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`foo.hello`), which consists of labels separated by dots. Policies and
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access is done on a name basis - if access to `foo` is granted, `foo.hello`,
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`foo.bar.hello`, etc. can be accessed, but not `bar` or `bar.hello`.
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## Components
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Albatross consists of a set of binaries. Several daemons, which communicate in a
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request-response style over Unix domain sockets, are run in the host system:
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- `vmmd`: privileged to create and destroy unikernels
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- `vmmd_console`: reads the console output of unikernels
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- `vmmd_log`: event log
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- `vmmd_stats`: statistics gathering (rusage, ifstat, BHyve debug counters)
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- `vmmd_tls`: remote deployment via TLS with client certificate, and proxies to local daemons
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- `vmmd_tls_inetd`: remote deployment via TLS and inetd (alternative to `vmmd_tls`)
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- `vmmd_influx`: statistic reporting from `vmmd_stats` to influx
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The main daemon is the privileged `vmmd`, which supervises unikernels. It opens
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a listening Unix domain socket, reads the persisted unikernel configuration,
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starts these unikernels, and awaits commands. Access can be regulated by Unix
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file permissions, only those users who can write to that socket can send
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commands.
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`Vmmd_console` does not keep any persistent state, but a ring buffer of console
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output from each unikernel. These messages can be retrieved by a client, as a
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stream of messages (history, and whenever a new line is output, it is send to
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the interested client). Each unikernel output can only be read by a single
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client, to avoid amplification of traffic if lots of clients are connected.
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`Vmmd` sends a message to `vmmd_console` whenever a new unikernel is started,
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upon reception `Vmmd_console` opens and reads the fifo which the unikernel will
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write their standard output to.
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`Vmmd_log` keeps a persistent event log for albatross, can be read by clients.
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`Vmmd_stats` gathers periodically statistics (memory, CPU, network, hypervisor)
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from all running unikernels.
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`Vmmd_tls` and `vmmd_tls_inetd` listen on a TCP port, and proxy requests from
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remote clients to the respective daemons described above. They enforce client
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authentication, and use the commen names of the client certificate chain as
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administrative domain. The policies are embedded in CA certificates, the command
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is embedded in the leaf certificate.
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The following command-line applications for local and remote management are provided:
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- `vmmc_local`: sends a command locally to the Unix domain sockets
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- `vmmc_remote`: connects to a remote TLS endpoint and sends a command
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- `vmmp_request`: creates a certificate signing request containing a command
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- `vmmp_ca`: certificate authority operations: sign, generate, and revoke (NYI)
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- `vmmc_bistro`: command line utility to execute a command remotely: request, sign, remote (do not use in production, requires CA key locally)
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## Installation
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To install Albatross, run `opam pin add albatross
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https://github.com/hannesm/albatross`.
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Init scripts for FreeBSD are provided in the `packaging/rc.d` subdirectory.
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TODO: from here on, this documentation is not up to date.
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It may help to read [the _outdated_ blog article](https://hannes.nqsb.io/Posts/VMM)
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for motivation of albatross and an overview over its functionality.
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