diff --git a/sys-cluster/nanos6/Manifest b/sys-cluster/nanos6/Manifest
new file mode 100644
index 0000000000..783a17df8b
--- /dev/null
+++ b/sys-cluster/nanos6/Manifest
@@ -0,0 +1 @@
+DIST nanos6-2.5.1.tar.gz 744260 BLAKE2B 6b294391ebb18806da76b4bc73aaf6f7082ab4a61693ab300e130f04942bf50c1da884e5271765465bedab863cb1ce545a43ac09727152c0a52d69852e60e373 SHA512 c7da862aa41fb0be1a992f4fde7306a02c4159c05a89055f0144bf6a815c10ff5f7e7ee11b4afaa4c468afdd538a99b3b5971a896221b20928805b45d35e0335
diff --git a/sys-cluster/nanos6/metadata.xml b/sys-cluster/nanos6/metadata.xml
new file mode 100644
index 0000000000..d72d9ec643
--- /dev/null
+++ b/sys-cluster/nanos6/metadata.xml
@@ -0,0 +1,29 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<!DOCTYPE pkgmetadata SYSTEM "http://www.gentoo.org/dtd/metadata.dtd">
+<pkgmetadata>
+	<maintainer type="person">
+		<email>lssndrbarbieri@gmail.com</email>
+		<name>Alessandro Barbieri</name>
+	</maintainer>
+	<upstream>
+		<bugs-to>https://github.com/bsc-pm/nanos6/issues</bugs-to>
+		<remote-id type="github">bsc-pm/nanos6</remote-id>
+	</upstream>
+	<use>
+		<!--<flag name="chrono-arch">use an architecture-dependent chrono for timing instead of the default one</flag>-->
+		<flag name="cluster">Enable OmpSs@Cluster support. This requires an MPI version that supports MPI_THREAD_MULTIPLE to be present in your environment</flag>
+		<!--<flag name="cuda">enable CUDA</flag>-->
+		<flag name="debug">enable extra assertions and checks in debug - may cause significant slowdown</flag>
+		<flag name="dlb">enable dynamic management and sharing of computing resources</flag>
+		<flag name="embed-code-changes">embed into the runtime any code changes present in the source</flag>
+		<flag name="execution-workflow">Enable execution using the Execution Workflow</flag>
+		<!--<flag name="extrae">to generate execution traces for offline performance analysis with paraver</flag>-->
+		<!--<flag name="jemalloc">use jemalloc as the default memory allocator, providing better performance than the default glibc implementation</flag>-->
+		<!--<flag name="k1om">specify the installation prefix of the k1om GNU compilers</flag>-->
+		<!--<flag name="memkind">specify the installation prefix of memkind</flag>-->
+		<!--<flag name="mercurium">specify the installation prefix of the Nanos6 Mercurium compiler</flag>-->
+		<flag name="papi">enable <pkg>dev-libs/papi</pkg> support</flag>
+		<!--<flag name="pqos"> to generate real-time statistics of hardware counters</flag>-->
+		<flag name="unwind">to generate sample-based profiling</flag>
+	</use>
+</pkgmetadata>
diff --git a/sys-cluster/nanos6/nanos6-2.5.1.ebuild b/sys-cluster/nanos6/nanos6-2.5.1.ebuild
new file mode 100644
index 0000000000..a49c3601ad
--- /dev/null
+++ b/sys-cluster/nanos6/nanos6-2.5.1.ebuild
@@ -0,0 +1,114 @@
+# Copyright 2019-2021 Gentoo Authors
+# Distributed under the terms of the GNU General Public License v2
+
+EAPI=7
+
+inherit autotools
+
+DESCRIPTION="runtime that implements the OmpSs-2 parallel programming model"
+HOMEPAGE="https://github.com/bsc-pm/nanos6"
+SRC_URI="https://github.com/bsc-pm/nanos6/archive/refs/tags/version-${PV}.tar.gz -> ${P}.tar.gz"
+
+LICENSE="GPL-3"
+SLOT="0"
+KEYWORDS="~amd64"
+IUSE="cluster debug dlb doc embed-code-changes execution-workflow git papi unwind"
+#chrono-arch build fail
+#jemalloc require custom stuff
+#TODO: cuda pqos mercurium memkind k1om extrae
+RDEPEND="
+	>=dev-libs/boost-1.59:=
+	sys-apps/hwloc
+	sys-process/numactl
+	virtual/libelf
+
+	cluster? ( virtual/mpi )
+	dlb? ( sys-cluster/dlb )
+	embed-code-changes? ( dev-vcs/git )
+	papi? ( dev-libs/papi )
+	unwind? ( sys-libs/libunwind )
+"
+#extrae? ( sys-cluster/extrae[nanos] )
+DEPEND="${RDEPEND}"
+BDEPEND="doc? ( app-doc/doxygen )"
+REQUIRED_USE="cluster? ( execution-workflow )"
+S="${WORKDIR}/${PN}-version-${PV}"
+
+src_prepare() {
+	default
+	eautoreconf
+}
+
+src_configure() {
+	local myconf=(
+		--disable-chrono-arch
+		--disable-openacc
+		--disable-static
+
+		--enable-shared
+
+		--with-boost="${EPREFIX}/usr"
+		--with-libnuma="${EPREFIX}/usr"
+		--with-pic
+
+		--without-k1om
+		--without-nanos6-clang
+		--without-nanos6-mercurium
+		--without-pgi
+
+		$(use_enable cluster)
+		$(use_enable doc doxygen-doc)
+		$(use_enable doc doxygen-dot)
+		$(use_enable doc doxygen-html)
+		$(use_enable doc doxygen-man)
+		$(use_enable doc doxygen-pdf)
+		$(use_enable doc doxygen-ps)
+		$(use_enable debug extra-debug)
+		$(use_enable embed-code-changes)
+		$(use_enable execution-workflow)
+	)
+
+	if use dlb; then
+		myconf+=( "--with-dlb=${EPREFIX}/usr" )
+	else
+		myconf+=( "--without-dlb" )
+	fi
+	if use embed-code-changes; then
+		myconf+=( "--with-git=${EPREFIX}/usr" )
+	else
+		myconf+=( "--without-git" )
+	fi
+#	if use extrae; then
+#		myconf+=( "--with-extrae=${EPREFIX}/usr/$(get_libdir)/extrae" )
+#	else
+		myconf+=( "--without-extrae" )
+#	fi
+	if use papi; then
+		myconf+=( "--with-papi=${EPREFIX}/usr" )
+	else
+		myconf+=( "--without-papi" )
+	fi
+	if use unwind; then
+		myconf+=( "--with-libunwind=${EPREFIX}/usr" )
+	else
+		myconf+=( "--without-libunwind" )
+	fi
+
+	econf "${myconf[@]}"
+}
+#		--without-pqos
+#		--without-jemalloc
+#		--without-cuda
+#		--without-memkind
+
+src_install() {
+	default
+
+	docompress -x "/usr/share/doc/${PF}/paraver-cfg"
+	docompress -x "/usr/share/doc/${PF}/scripts"
+}
+
+pkg_postinst() {
+	elog "install media-gfx/graphviz and app-text/pdfjam or >=app-text/texlive-core-2021 to generate graphical representations of the dependency graph"
+	elog "install sys-process/parallel to generate the graph representation in parallel"
+}